The scandal threatening to engulf the News of the World will intensify this week when the Metropolitan police hands over previously undisclosed documents relating to the hacking of celebrities' mobile phones while the paper was edited by Andy Coulson, David Cameron's communications director.

The documents are expected to trigger fresh allegations that phone hacking at the paper was extensive and not the work of "one rogue reporter" as it has maintained. The fear for News International, the parent company of the News of the World, owned by Rupert Murdoch, is that the documents may contain the names of commissioning journalists.

Scotland Yard has until Wednesday to comply with a court order obliging it to provide lawyers representing the sports agent Skylet Andrew with material relating to the hacking of his phone which was recovered by police from the offices of Glenn Mulcaire, a private investigator in the pay of the newspaper.

Andrew, who represents Ashes hero James Anderson, the former England footballer Sol Campbell and the Stoke City player Jermaine Pennant, is one of the leading sports agents in the UK.

The imminent disclosure comes as the News of the World defends itself against a legal action brought by the actor Sienna Miller. Ian Edmondson, the News of the World assistant editor, has been suspended amid allegations he sanctioned the hacking of Miller's phones. His suspension triggered a request from Scotland Yard for the newspaper to share any new information it had on the scandal.

Disclosure of Andrew's files is viewed by lawyers as of equal significance to the Miller revelations. The documents relate to the original 2006 hacking case involving the interception of royal aides' phones that resulted in the jailing of Mulcaire and the paper's former royal editor and gossip columnist Clive Goodman. During the trial, Mulcaire also pleaded guilty to intercepting the phones of Andrew and four other high-profile figures.

At the time the News of the World denied knowing anything about this additional hacking which, along with Andrew, involved the supermodel Elle Macpherson, the MP Simon Hughes, the publicist Max Clifford, and the former head of the Professional Footballers' Association, Gordon Taylor.

Clifford, however, sued the newspaper, dropping his case only after accepting a reported £1m to settle out of court, a move that meant all the files taken from Mulcaire's office by the Met and disclosed to the publicist's legal team never made it into court. Taylor also settled for a substantial sum, a decision that again meant potentially damaging files never entered the public domain.

But Andrew has pursued a low-profile legal action, and the release of the Met's files relating to his case, which must also be shared with lawyers representing the News of the World, means the newspaper could yet be forced to defend itself in court.

Andrew's legal team will be keen to discover to what extent, if any, the files refer to Goodman, Edmondson, Greg Miskiw, the paper's former assistant editor, and its chief reporter, Neville Thurlbeck, who all face allegations they knew phone hacking was taking place. Rupert Murdoch, when questioned about the affair last year, said: "There was one incident more than five years ago ... the person who bought the bugged conversation was immediately fired. If anything was to come to light, and we have challenged those people who have made allegations to provide evidence ... we would take immediate action."

Coulson, who resigned as editor of the News of the World after Goodman and Mulcaire were sentenced, has denied knowing hacking was taking place on his watch. David Cameron has staunchly defended his director of communications. But investigations by the Guardian suggested phone hacking was widespread on the newspaper under Coulson.

News International faces questions about whether it will offer Edmondson a pay-off to leave the paper or whether it will itself take legal action against its senior employee. Further pressure on News International will come this week when a cross-party parliamentary committee again discusses the scandal. The Observer understands that in the past few days several more celebrities whose phones were also allegedly hacked, have signed up with law firms to bring actions against the newspaper.

Today a spokesman for News International said it had no comment. A spokeswoman for the News of the World also declined to speak.