MPs investigating allegations of widespread use of private investigators by the News of the World to hack into phones were handed documents today revealing that more journalists were involved in the practice than the paper’s owner, News International, has previously admitted.

During testimony to the Commons committee on culture, media and sport, the Guardian investigative reporter Nick Davies produced previously unseen records which showed that two senior figures on the paper as well as a junior reporter had a role in obtaining the contents of private voicemail messages through a private investigator.

News International has previously insisted that only one of its journalists, the royal editor, Clive Goodman, had used this illegal method. He was jailed for four months in January 2007, along with a private investigator, Glenn Mulcaire.

Yesterday Davies handed over copies of an email from an unnamed junior News of the World reporter to Mulcaire that also referred to the paper’s chief reporter, Neville Thurlbeck. In the email, the reporter says: “Hello, this is the transcript for Neville.” Davies told the committee that the email, dated 29 June 2005, contained “a typed-up transcript of 35 messages which Mulcaire had hacked from the telephones of Gordon Taylor, chief executive of the Professional Footballers Association, and Jo Armstrong, a legal adviser at the PFA”.

The second document handed to MPs was a contract dated February 2005 between the News of the World assistant editor Greg Miskiw and Mulcaire – who was using an alias, Paul Williams. In the document, Miskiw promises Mulcaire a bonus of £7,000 if he delivers a specific story about Gordon Taylor.

The Guardian revealed last week that Taylor, Armstrong and a third person were paid a total of more than £1m in costs and damages by the News of the World’s parent company, News Group, to settle a lawsuit for breach of privacy and to keep it secret. Davies told the committee: “It is hard to resist the conclusion that [News International] have consistently admitted only what has been dragged into the public domain and is indisputable.”

The Guardian’s editor, Alan Rusbridger, who was also giving evidence to MPs, said the Taylor story was significant “because it undermines the assurances given both to you and the PCC [Press Complaints Commission] about the sole reporter and the sole detective – the so-called rotten apple defence”. He continued: “News International have known about the involvement of other journalists, including at senior level, for at least a year. It is believed the case [Gordon Taylor] was settled last September. So that begs the question: why they did not tell the PCC, the regulators, or this committee, of the new facts that have come to light.”

The Conservative party’s director of communications, Andy Coulson, who was editing the News of the World at the time of the Goodman case, resigned when Goodman was convicted.

Both documents produced by the Guardian today had been seized by police during the Goodman case.

Rusbridger said the Guardian story was not “a campaign to oust anybody”.

“It wasn’t a campaign to reopen the police inquiry, or to call for prosecutions or to force anybody to resign. We have not called for any of those.

“As a paper we do believe in effective self-regulation and we don’t want a privacy law. When it comes to effective self- regulation, it seems to me it can only work if newspaper groups are truthful and open with the regulators.”

He suggested to MPs that a possible way forward for newspaper editors would be to draw on a definition of the public interest proposed by the government’s former security co-ordinator Sir David Omand.

John Whittingdale, who chairs the culture committee, said the Guardian’s revelations “raised questions” about the extent of phone hacking at the tabloid. News of the World editor Colin Myler and Tom Crone, the paper’s in-house lawyer, will give evidence to the MPs next week.

It also emerged today that the Home Office questioned the decision by Scotland Yard’s assistant commissioner, John Yates, not to reopen the Met’s phone-tapping investigation.

An exchange of letters placed in the House of Commons library discloses that Stephen Rimmer, the Home Office’s director general of crime and policing, wrote to Yates last Friday asking what the Met was doing about the allegations about the involvement of 27 other journalists and whether the police would be informing all those allegedly targeted.

Yates’s reply, sent the same day, said that he had not conducted a review and said he had only been asked by the Met commissioner to establish the facts in the light of the Guardian’s articles in connection with the 2005 police investigation.

Yates’s confirmation that the original investigation did not cover any other journalists has fuelled demands at Westminster that Scotland Yard reopen its investigation. Its understood the Commons home affairs select committee is also likely to open its own investigation into the police failure to look into the wider allegations unless it receives a satisfactory explanation by the end of this week.