In the absence of a suitable local authority the Board of Trade Traffic Branch took charge of the construction of arterial roads in the London area under the supervision of its Chief Engineer Colonel Hellard. In due course a Greater London Arterial Roads Conference was set up and working with the newly formed Ministry of Transport by 1924 considerable progress was being made and much of the North Circular Road (A406) was under construction or completed between Hanger Lane in the west and Gants Hill in the East although much of this was to constricted standards with at grade intersections. By 1936 only 4 miles of its 19-mile length were dual carriageway and 12 miles had carriageway no wider than 30 feet. In the South however little progress was made with the 15 mile route from Wandsworth Bridge in the west to the Woolwich Ferry in the east. It was only in 1935 that a continuous, if rather tortuous, chain of streets could be linked together to form a very substandard South Circular "Road".

Whilst these two half orbitals would have been co-terminus in the east at a new tunnel in the vicinity of the Woolwich Ferry this would not have been the case in the west. Here the most direct link between the two would have been a new route - the Wandsworth Bridge to Watford by Pass linking to the A41 at Cricklewood and thence onward to the A406.

Within the area encompassed by the North and South Circular Roads there was no coherent orbital route and no proposals for one until after the Second World War.

The responsibility for the planning of major roads in London and the South East was a rather muddled affair before the Second World War and some would argue remains so. Major road proposals in the region had been conceived by the Local government Board between 1913 and 1916 in the form of the Greater London Arterial Road Programme. Little progress was made with implementing these proposals until the newly created Ministry of Transport offered help with the programme largely to help relieve post war unemployment. The late 1920s saw the completions of isolated sections of the north and south orbitals (more in the north than the south).

 The Highways Development Survey 1937

The first coherent proposal for an orbital road around Greater London was contained in the plan drawn up by Sir Charles Bressey (Engineer to the Ministry of Transport) and his consultant Sir Edward Lutyens. This was prepared following an instruction in 1934 from the then Minister of Transport (The Right honorable Leslie Hore-Belisha) to put in hand a comprehensive and systematic survey of the highway developments required in the London Traffic Area during the next thirty years in order to keep pace with the expansion of traffic. The number of road vehicles in Great Britain had risen to a total of 2.4m at that time from less than a quarter of a million in 1912 and under one million in 1922. Bressey and Lutyens observed that the continuous built up area of greater London had extended six miles outwards along the main radial roads between 1905 and 1935 and that that, despite a long term reduction in the number of people living in the Administrative County of London (the LCC area), the population of greater London was growing faster than the national average.

The population of Greater London was forecast to grow from its figure of 9,400,000 in 1935 to 10,760,000 in 1951 at which point it would stabilize. However the outer areas were expected to gain even more population as these totals included a continuing decline in the LCC area. And it was here that the growth in traffic pressures would be greatest.

Bressey and Lutyens carried out surveys of speeds on three radial routes each of 12.6 miles in length and along the North Circular (22.75 miles). They observed that speeds on the radial routes averaged 12½ mph whilst those on the North Circular averaged 23.6 mph. This was interpreted as a clear sign that well designed orbital roads provided effective by passes to congested urban areas and that upgrading of the South Circular Road should be a high priority.

Today traffic speeds in Inner London average about 12¼ mph but a direct comparison between this and the 12½mph in 1935 could be misleading for two reasons. Firstly the current figures include a much larger network of roads and secondly the survey methods were different. Modern "floating car" surveys are designed to discover the actual average speeds. The Bressey and Lutyens survey used a different methodology:

"Each of the four routes was traversed continuously by a 16 H.P. Austin Light Six Touring car during a six day working week (Sunday excluded). From Monday to Friday inclusive, the car ran driven by a steady and competent professional chauffeur, who had no inducement to attempt to break records or take risks. His pace may be assumed to be that of the punctilious cautious and considerate driver who presumable constitutes the bulk of the British motoring community."

Bressey and Lutyens also carried out an early Origin and Destination survey of traffic to and from the London Docks, which was a major source of road traffic in the 1930s. Despite these early attempts at traffic analysis there is little evidence in the report by Bressey and Lutyens of a systematic assessment of prospective traffic needs and alternative ways of meeting these. However it was able to come up with a comprehensive set of proposals, some new but many borrowed from earlier assessments of the need for highways improvements.

Amongst these proposals was one for North and South Orbital Roads. These were to be constructed at a distance of 18 to 20 miles out from Charing Cross and followed routes that had been developed by the local Highway and Town Planning Authorities since 1926. The North Orbital route "extends from a new bridge over the Thames at Egham to Brentwood via Uxbridge, Watford, Hatfield, Hoddeston, Epping and Chipping Ongar. At Brentwood the route divides, one branch forming the northern approach to the lower Thames Tunnel (now in the course of construction) and the other branch running further eastward to terminate at Tilbury. The line of the route has in a large measure been safeguarded, and portions are already being constructed between Uxbridge and Rickmansworth and between Watford and Hatfield. In all cases the route is planned to avoid built-up centres."

"The complementary project of a South Orbital Road, upwards of 50 miles in length, would start at the proposed new bridge over the Thames at Egham where the North Orbital terminates and continue on a line between Thorpe and Virginia Water Station to the New Chertsey Road, part of which would be included. Thereafter the line would run to New Haw, bridge the River Wey Navigation, pass through Byfleet, cross the river Wey and absorb the existing road over Okham Common. Continuing north of Great Bookham Common, the route would strike the Leatherhead-Guilford Road near Fetcham and trending eastward would skirt, Kingswood, Merstham, Godstone, Oxted and Westerham. Here the line would swing north-eastwards past Schevining, Shoreham and Eynsford thus improving road communications to the future airport at Lullingstone. East of Swanley Junction the route would join the southern approach to the Lower Thames Tunnel, through which connection would be made to the North Orbital Road.

Intersecting all the main radials south of London, the South Orbital Road will act as a feeder to the Lower Thames Tunnel and will deflect through traffic from the congested inner areas of the Metropolis.

The route as planned passes through some of the finest scenery in Kent and Surrey and the whole route should be treated as a parkway, with access restricted and "flyovers" provided at all major crossings. No route could be better adapted than these orbital roads to give access to the open spaces forming London's Green Belt." 

The Bressey/Lutyens route for the South Orbital is closely shadowed by the M25 as built. Between Egham and Addlestone the two routes are much the same but from here the M25 takes a slightly wider sweep past New Haw and Byfleet to the north of Great Bookham Common. There the routes diverge with the M25 passing to the north of Leatherhead where Bressey and Lutyens would have their road go to the south. The two alignments then cross at Walton on the Hill, this time with the M25 to the south, cross again to the west of Merstham with the M25 taking the inner line. The alignments converge about a mile to the east of the A22 and follow the same route to the A224 from their the Bressey Lutyens route passes a mile or so to the east of the M25 alignment to rejoin it at the A20 where they follow the same route to the Dartford Crossing (the construction of the Dartford Tunnel had commenced in April 1936 but was not expected to be completed 'till 1947). (The history of this early tunnel can be found on this link).

The North Orbital proposed by Bressey and Lutyens was a rather different proposition. Unlike the South Orbital which made little attempt to pick up existing sections of road en route (there being hardly any suitable sections) the North Orbital attempted to incorporate a number of sections of existing road and especially those parts of the North Orbital which had been built following alignments in Colonel Hellard's 1910 Plan.

In the east the route the route was formed of two branches south of Brentwood: one linking down to the Dartford Tunnel and the other to Tilbury. The inner route followed the Purfleet by Pass and the A13 as far as Wennigton where it struck a new alignment northwards to pass by the east of Rainham - inside the route of the M25. It then traversed northwards to the west of Hacton passing between Upminster and Hornchurch at Winglety Lane. Skirting the eastern edge of Emerson Park it crossed the A127 passed to the west of Tylers Common intersecting the A12 at the same point as the existing M25. However from this point it went around the east side of Weald Park to join with the eastern branch at Pilgrims Hatch. 

The eastern branch began north of Tilbury at Chadwell St Mary - twenty one miles from central London where it picked up from an improved Feenan Highway and ran north through Bulpham to pick up the A128 (Tilbury Road which it followed to Herongate where it then took a new alignment to the east of Ingrave skirting Brentwood to rejoin the A128 at Pilgrim's Hatch to join the route linking down to Dartford. At this point it would have been about two miles further out from London than the M25. From Pilgrim's hatch it would have swept up to the west of Kelvden Hatch where it would once again have joined the A128 which it would leave at Langford Bridge Farm and follow a new route to the south of Marsden Ash passing to the north of Ongar Park Wood and Epping Forest to cross the B1393 at Thornwood. Where it was 2½ miles distal of the M25. From here it continued on a virgin alignment via Epping Green, Broadley Common and Netherton Common where it tracked west, south of Hoddeston town centre and across north of Brickenden to pick up the alignment of the B158 (Essenden Road) and then on via Holwell lane to the A414 (Hertford Road) at its junction with Hatfield Road. At this point the route was at its most northerly being 18 miles north of central London and almost five miles further out than the M25. From thereon the route followed the A414 curving south to pick up the Barnet By Pass (A1001) to where it connected with the existing north orbital at Roe Green. From this point it followed the A414 and then the A405 on around the north of Watford to connect with the A41 from which it once again took off on a new alignment which essentially is that of the M25 today. However it only followed this as far as the south of Chorleywood where it once again adopted an existing alignment: that of the A412 (Denham Way), which it followed southwards to join the A40 west of Denham. From there it shared the alignment of the A40 to what is now the Denham roundabout and then on along the A4029 to new Denham where it struck of a virgin alignment to Iver Heath. At this point it was once again on the outside of the M25 and followed a new route southwards, crossing the Grand Union Canal and the Great Western Railway swinging to the west of Colnbrook. From here it veered south east to drop through what is now the axis of the Wraysbury Reservoir to pick up the alignment of today's M25 at Runnymede Bridge.

Bressey and Lutyens clearly recognized the difficulties that would be involved in widening existing roads and so turned their attention to the possibilities for new routes. They considered the potential for building roads over railways. However they concluded that this was not a practical option on any significant scale because the necessary wayleave widths would blight adjacent properties, construction would be costly and the problems of traversing road over-bridges and where the railways went into tunnel would be formidable. However they saw this as a technique that might be employed in exceptional circumstances.

Although no motorways had been built in 1937 there had been several proposals for such types of roads and, at the time, Lancashire County Council was proposing to build a North/south motorway through the County. In due course this proposal would gestate into the M6. Bressey and Lutyens took the view that motorways should not necessarily be subject to tolls as most schemes 'till then had envisaged. There attraction to motorways arose from the prospect of rapid unimpeded movement of motor vehicles, reduction of traffic on multi-purpose arterials and the avoidance of damage to property and other "cherished features which cluster along the old main roads". However Bressey and Lutyens stopped short of proposing specific motorways but stuck to the Ministry's guidelines for road widths ranging up to 140 feet. Whilst for the open sections of the South Orbital it was suggested that the Parkway approach should be followed for other main routes an design integrated with the adjacent buildings and spaces was advocated especially in the vicinity of roundabouts.

By the time Lutyens and Bressey's Highway Development Survey was published the prospects of war were looming and the Country's attention was turning to more pressing matters but there was to be one more plan proposing a new London orbital road to be published before the war took its hold. In 1938 the Modern Architectural Research group published its outline plan for London and this included a road around London running from Purfleet in the east up to Navestock thence across North London to Radlett but taking a gently concave rather than convex routs. Here it turned south/west to Windsor then east/south/east to Epsom to Shoreham and thence back up to Purfleet. It was clear that by this time an outer orbital high quality road had become an established feature of the Greater London planning scene.

In 1944 the "Abercrombie Plan" for Greater London was published. This was the third of a set of related plans covering the City of London, the Administrative County of London and "Greater London" comprising an area stretching out to about 30 miles from the centre and covering 2,599 square miles. Neither of the two earlier plans addressed the issue of an outer orbital road but the County of London Plan envisaged a basically ring and radial main road system with a "C" ring which was based on Route No 19 as proposed by Bressey and Lutyens with changes to the proposed route in Fulham/Wansworth, Catford and Woolwich. However the Plan was attracted to the merit of Parkways, as was the report on it by the Chief Engineer of the LCC.

The 1944 Plan was based on assumptions that the population of Greater London would reduce slightly and would be distributed (in an orderly manner) away from the crowded central/inner areas to the suburbs and beyond. It also assumed that the recommendations of the Barlow report that, as a general rule, no new industry should be admitted to London and the Home Counties. Finally the Plan assumed that Port of London would continue to be one of the world's great ports.

The structure of London was envisaged as four concentric rings: the Inner (old urban core) ring the Suburban ring, the Green belt Ring and the Outer Country Ring which accommodate population and industry displaced out from inner London in expansions of existing settlements and the creation of new satellite developments.

The roads and traffic proposals in Abercrombie's plan were strongly influenced by Alker Tripp (the Metropolitan Commissioner of Police) and acknowledged traffic expert) and differed from the approach of Lutyens and Bressey in distinguishing clearly between an arterial network and an entirely new system of "motorways". Although this differed from the proposals of Lutyens and Bressey it carried their justification for building motorways to its logical extreme. The 1944 plan added two outer orbital routes to the three contained in the County of London Plan (along with ten radials) making five in all being:

• the "A Ring": a sub-arterial route encircling an extended central area
• the "B Ring": an arterial for fast traffic reaching to Earls Court in the west, the Isle of Dogs in the east, Islington in the north and Dulwich in the south
• the "C Ring": a sub-arterial formed of the north and south circulars
• the "D Ring": an express arterial just outside the built up area
• and the "E Ring": a sub-arterial comprising the north and south orbitals

Of these five rings The B Ring and the D Ring were seen to be the most substantial and giving most relief to the underlying arterial roads network.. The reasons given for putting greater emphasis on the D Ring rather than the E Ring was that Bressey's proposal (on which a start had been made) was too far out to afford relief to inner London or to regional traffic requirements. However it was recognized as "an admirable Parkway route that would provide for intercommunication between towns and by pleasure traffic".

The 1944 plan largely adopted the alignment for the north and south orbitals proposed by Bressey and Lutyens except for the arc between Dunford Green in Kent and Chipping Ongar in Essex where the rather incoherent Bressey Ring was omitted completely. This is presumable because the D Ring reached out to cross the River Thames at Dartford in the east which, along with the lower traffic densities in this sector, obviated the need for any further orbital road capacity to be added further out. Its omission also saved the expense of what would have been a costly river crossing.

The trilogy of plans produced in 1943 and 1944 contained thoughtful analysis and many sound proposals. Indeed some of the key ideas in those plans endured for many years and became the foundation for subsequent policy and action. However they were not statutory plans as this process had to await the 1947 Town and Country Planning Act. As far as motorways were concerned there was no suitable legislation to enable the construction of these until the passing of the Special Roads Act in 1949. Despite the passing of this Act little was done to implement the road proposals in the 1943 and 1944 plans. This is exemplified by the statement in the Administrative County of London Development Plan of 1955: - "It is not yet possible to contemplate a drastic re-arrangement, including motorways, of the main road system. It is therefore the Council's intention that the main highway structure of the Administrative County shall be based on the existing network of principal traffic roads, improved where practical by reconstructed intersections, widening roads or construction new sections of routes on a comprehensive and co-ordinated basis."

 The London Traffic Survey and the Greater London Development Plan

By the late 1950s traffic conditions in the London Area were deteriorating rapidly. A number of initiatives were put in hand to try and slow this including the introduction of parking meters and a major programme of traffic management lead by the London Traffic Management Unit which was set up specifically for that purpose. It also became widely accepted that London's traffic and transport problems needed to be dealt with on a metropolitan basis rather than the patchwork of County Boroughs and County Councils clustered around the London County Council (LCC) whose area of jurisdiction was determined back in the 1888.

Accordingly in December 1957 a Royal Commission (the Herbert Commission) was set up to look into arrangements for metropolitan governance. This took the area defined by the Registrar General as the Greater London Conurbation. This stretched from Banstead in the South to Cheshunt in the north and Uxbridge in the West to Hornchurch in the east into its consideration - an area of 842 square miles, quite similar to that bounded by the M25 and a population in 1959 of 8.714m. This area was much smaller than the London Traffic Area as defined in the London Traffic Act of 1924 and the even larger London Passenger Transport Board Area created nine years later in 1933.

In its recommendations the Herbert Commission chose to take a rather narrow view of what comprised Greater London and recommended an even smaller area that subsequently became the 624.7 square miles of Greater London under the jurisdiction of the Greater London Council (GLC). So, despite the fact that the Commission concluded that the traffic and highway problems of London were insoluble without appropriate administrative reform and, despite the fact that it concluded that a single authority should be responsible for the construction, maintenance and lighting of all main roads, it arrived at an area which had only short sections of the proposed London Orbital road in it. By its own logic the problems that it had tried to solve for the inner roads were now to be visited on the outer orbital.

Of course the choice of area had to be a compromise between the logical areas for the several key services for which the GLC was to take responsibility. Similarly it would be naïve to suppose that the desire of the Home Counties to limit the absorption of some of their most prosperous areas into the new Greater London administrative area and it could be that the area chosen was the optimum compromise. However, whatever it may have done for other projects and services the choice of this rather restricted area did nothing for furthering the cause of the London Orbital.

Just over a year after the report of the Herbert Commission, in December 1961, the LCC and the Ministry of Transport set up the London Traffic Survey. This was required to make a comprehensive survey of travel in Greater London and to provide forecasts of how this would change in future. Subsequently in Phase III of what, by then, had become the London Transportation Study (LTS) the consultants (a joint venture of an American firm - Wilbur Smith and Associates and a British engineering consultancy - Freeman Fox and Partners) a range of plans and policies were tested and evaluated.

Phase I of the study was reported on in 1964 and set out the most comprehensive account of travel by all forms of transport in the LTS area, public (rail as well as road) and private and passenger and goods. The study area extended over 941 square miles and so was half as big again as the shortly to be created Greater London administrative area. However it was not sufficiently large to enclose the whole of the M25 let alone an external collar which would have been necessary for it to be properly analysed as a road option for the London area. The consultants recognized this shortcoming and the surveys included traffic movements to from and between areas outside the LTS area but which passed through it. However despite this the traffic assignments to the motorway networks almost certainly failed to reflect fully the traffic that would have been drawn in to use the outer orbital.

Phase II of the study, which was reported on in 1966, went on to develop forecasting procedures and produce estimates of travel patterns in 1971 and 1981. This made it quite evident that unrestrained growth of road travel would place a huge burden on London's road network, which would have to be mightily expanded if it were to bear this without extensive congestion. The analyses in Phase II of LTS also made it clear that the demand for orbital road capacity would be the most acute and unrestrained assignments of traffic gave daily flows in excess of three hundred thousand vehicles a day on the western arm of what was to be called the Motorway Box and approximated to the B Ring in Abercrombie's Greater London Plan.

As a result of these rather alarming findings a revised approach was adopted in Phase III of the study. This revised approach required development of the analytical techniques to address issues beyond the effective scope of the conventional US based methods that had been used in the first two phases. These developments included a sophisticated form of public transport analysis, traffic restraint procedures and economic evaluation capable of dealing with multi-modal transport plans.

A number of motorway systems were tested in Phase III of LTS and three were chosen for detailed evaluation. All of these (Plan 1. Plan 3 and Plan 10) included an outer Orbital and Plan 1, which had the least length of motorways in it, comprised just the Orbital plus those sections of radial motorways which were built or committed in addition to the base road system. This outer Orbital was termed the "D Ring" in LTS Phase III but followed a route similar to the M25 in the north east but was routed closer in to London in the south and west passing through Ruislip, Southall to the east of Heathrow and passing through the southern suburbs three or four miles inside the M25 alignment to join it east of Chelsfield. This route was just over one hundred miles in length compared with the 117 miles of the M25.

Plan 1 was not subject to an economic evaluation as it was used as the base case against which the more extensive motorway networks were tested. However the analysis concluded that Plan I would carry 13.3m vehicle miles in 1981 without traffic restraint and 11.5m with restraint. It is fair to conclude that the volume of traffic on the orbital, which comprised over two thirds of the length of motorway in the plan would have had about 8m vehicle miles per day assigned to it thus making average loadings of about eighty thousand vehicles a day.

The Greater London Development Plan (GLDP) was prepared by the Greater London Council as the statutory development plan for Greater London. As such, whilst having regard to the rest of the metropolitan area and the South East, it focused on the 620 square miles of Greater London. The motorway proposals also based on the findings of the London Transportation Study which had included a D Ring but no orbital beyond. It is not surprising therefore that, although the GLDP recognized proposals for the North and South Orbitals outside London it proposed a complete D Ring in the Plan (even though long sections of this lay beyond the GLC boundary) and took the view that "The Council considers that their construction is less urgent than the establishment of the primary road network, including Ringway 3 within London's boundaries." The outer orbital remained an orphan.

The GLDP was subject to an exhaustive Public Inquiry overseen by a Panel chaired by Frank Layfield. Many objections were lodged to the provisions of the GLDP and most of these were in respect of the proposed Motorway network either in whole or in part. In one case (the objection from the London Amenity and Transport Association) this took the form of a book: Motorways in London. The Layfield Inquiry took quite a different view of the need for Motorways in London from that of the GLC. Whilst supporting the concept of an inner London Motorway based on Ringway One (the most controversial of all the road proposals). It recommended that the southern section of Ringway two and the whole of Ringway Three (as the D Ring had now become called) be dropped from the GLDP the reasons for this being summarized thus "We, therefore, recommend rejection of Ringway 3 because the orbital road outside London is already virtually committed and does not need duplicating." With acceptance of this when the GLPD was subsequently confirmed clearly signaled that the M25 would have a major role in handling orbital movements in the outer London suburbs as well as the areas outside.

Prior to the Second World War the issue of an outer orbital road for London had been largely a regional issue and it is not surprising that little progress had been made given the absence of an effective regional government and the control of resources by central government. After the War this started to change. Increasingly professional and trade associations were looking to the government to take a lead on a national roads programme and in 1946 the Trunk Road Act extended the length of roads under the Ministry of Transport's direct jurisdiction from 3,685 miles to 8,190. By this time there had been a number of proposals for a national motorway network including those from the Institution of Highway Engineers in 1936 and the County Surveyors Society in 1938. The IHE scheme included an orbital motorway around London so putting this concept on the national agenda.

Whilst the concept of an London outer orbital road had been a live issue since 1905 official road planning had usually treated it as two roads - the North and South Orbitals - rather than a single entity and complete ring in itself. Even today the M25 does not completely encircle London as the eastern crossing at Dartford is formed of the A282 which is a general purpose road partly in Kent and partly in Essex linked by the Dartford tunnel and bridge which are tolled highways.

This situation existed up until 1975 with the M16 outer orbital in the north and the M25 in Kent and Surrey in the south. In November 1975 the then Minister of Transport, John Gilbert, announced that these would be subsumed into a single ring - the London Orbital Motorway (M25). At that time there were still vain aspirations that there would be an inner ring motorway similar to Abercrombie's "C Ring", incorporating the North Circular Road (A406) - the M15.