A senior reporter at the News of the World was arrested today by detectives investigating phone hacking at Britain's biggest-selling weekly newspaper.

James Weatherup is being questioned at a London police station, sources said.

He is the third person arrested since London's Metropolitan Police reopened their investigation into claims that News of the World staff hacked into the mobile phone voicemails of celebrities and politicians to obtain stories.

The Sunday tabloid's owners, Rupert Murdoch's News International, issued a public apology last week for phone hacking and admitted liability in some cases, saying its actions had been "unacceptable".

Actress Sienna Miller is believed to be among those offered settlements from a ?20 million compensation fund set up by the company.

But Miller is believed to want the full extent of the phone hacking revealed in open court and shows no sign of accepting a compensation payment and dropping her legal action.

In 2007, the initial police investigation into phone hacking at the News of the World led to the convictions and jailing of paper's royal correspondent Clive Goodman and private investigator Glenn Mulcaire.

It emerged they had hacked into the mobile phone messages of Princes William and Harry to obtain information for use in stories.

Until the apology issued tomorrow, the News of the World had continued to insist that Goodman and Mulcaire were acting alone.

Last week, police arrested chief reporter Neville Thurlbeck, 50, and 42-year-old Ian Edmondson, the former assistant editor (news).

The phone hacking scandal caused the tabloid's former editor, Andy Coulson, to quit as head of communications for Prime Minister David Cameron.

Coulson had resigned as editor when Goodman was jailed but insisted he knew nothing of the phone hacking. He continues to deny wrongdoing, but said the continuing scandal was distracting him from his duties with Cameron.

A spokeswoman said News International had no comment to make on the latest arrest.