David Cameron is braced for tough questions from MPs about his party's links to a phone-hacking suspect, as he prepares to make an emergency statement on the scandal to the House of Commons.

The summer parliamentary recess was delayed by a day as the prime minister scheduled a statement in which he is expected to announce the names of the panel that will look at press regulation and the final terms of reference for the judge-led inquiry into claims about phone hacking and illegal payments to police.

The Commons debate – following a battery of revelations around phone hacking that have surfaced in the last week – comes as a report by the all-party home affairs select committee concludes that Rupert Murdoch's News International "deliberately" tried to block a Scotland Yard criminal investigation into phone hacking at the News of the World.

The committee brought forward the publication date to be ahead of the prime minister's statement.

The report finds the company deliberately tried to "thwart" the 2005-2006 Metropolitan police investigation into phone hacking carried out by the News of the World.

The police investigation came at a time when Andy Coulson was editor. Coulson was later hired by Cameron to be his director of communications, before resigning in January 2011.

The cross-party panel of MPs appears to have been convinced by evidence from senior officers who were involved in the case that News International obstructed justice, in a report published on Wednesday morning.

The revelations will add to the pressure on Cameron, who arrived home from a shortened trip to Africa on Tuesday night as the crisis deepened after it emerged that Neil Wallis, the former News of the World deputy editor arrested last week over allegations of phone hacking, was an adviser to the Conservative party before the general election.

Wallis helped Coulson in 2009 in preparations for the election campaign. Both men have been arrested and bailed in connection with the Scotland Yard hacking inquiry.

A Conservative spokesman has insisted Wallis was never employed by the Conservative party and had not been paid.

He added: "It has been drawn to our attention that he may have provided Andy Coulson with some informal advice on a voluntary basis before the election. We are currently finding out the exact nature of any advice.

"We can confirm that, apart from Andy Coulson, neither David Cameron nor any senior member of the campaign team were aware of this until this week."

The prime minister, who faces criticism for his handling of the crisis, decided to cut his visit to Africa by half last week as the hacking scandal deepened, and scaled it back by a further seven hours in order to return in advance of his Commons statement.

During a visit to Nigeria on Tuesday, he said the judicial inquiry would "get to the bottom" of the problems that have surfaced, but sought to keep the focus on the issues that "really matter" for the country, such as jobs and growth.

But Cameron – whose statement comes in the wake of an extraordinary series of Commons committee hearings involving Rupert and James Murdoch, Rebekah Brooks and senior police officers – is expected to face tough questions in a parliamentary debate billed to last until 7pm on Wednesday.

Jeremy Hunt, the culture secretary, rallied to the prime minister's defence, saying he had acted decisively "to sort this out".

He told BBC Breakfast: "What we've seen is that he's recalled parliament, he's got an independent police inquiry, he's got an independent judge-led inquiry, he's published all the meetings he's had with media owners and said in the future ministers will publish all the meetings that they have with media proprietors.

"So he's done more in a couple of weeks than, I think, any other prime minister has done in a couple of decades."

Hunt also insisted that Ed Llewellyn, Cameron's chief of staff, was right to ask John Yates in September 2010 not to brief the prime minister about the latest developments in the phone-hacking case.

Responding to the comments of the Met assistant commissioner, who resigned on Monday, Hunt said: "We don't know exactly what it was John Yates wanted to brief him about, but we do know it appears that it was about operational police matters and there is a very strong convention in this country under the separation of powers.

"Politicians don't involve themselves in operational police matters, so that the police are in no way compromised."

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