The police investigation into phone hacking at the News of the World has taken a dramatic turn with the surprise arrest of James Weatherup, a senior journalist at the paper.

He is the third current or former News of the World journalist to be arrested as part of Scotland Yard's new investigation into alleged phone hacking at the paper.

Weatherup, who has not previously been named in connection with the scandal, was arrested early on Thursday. He is currently in custody at a police station in outer London.

There are also expected to be further searches of the News of the World offices in Wapping shortly. It is thought that police felt the paper had failed to be fully co-operative during searches last week and officers are now determined to be more robust.

Weatherup was news editor at the News of the World for about 18 months from 2004, and was one of the inner circle of executives under the then editor, Andy Coulson, who became David Cameron's director of communications until earlier this year.

As the third news editor at the paper under Coulson, Weatherup was one of a handful of senior employees who would take part in private discussions of major news stories with other senior members of the paper.

Weatherup subsequently returned to being a senior reporter on the newspaper. He is a close colleague of Ian Edmondson and Neville Thurlbeck, who were arrested last week on suspicion of conspiring to intercept mobile phone messages.

Edmondson, the paper's former assistant editor (news), was dismissed in January. Thurlbeck is the News of the World's chief reporter.

Thurlbeck and Edmondson were arrested after voluntarily presenting themselves at different police stations in south-west London.

Both men were later released on police bail to return in September. Their homes, as well as Thurlbeck's office and computer at the News of the World offices, were searched by police.

It is believed Edmondson, who was sacked from the News of the World in January, and Thurlbeck have been implicated in the long-running scandal through documents seized from Glenn Mulcaire, the private investigator employed by the newspaper. Both Edmondson and Thurlbeck deny any wrongdoing.

News International had not responded to a request for comment at the time of publication.

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