Labour's chief fund-raiser Lord Levy last night accused police of whipping up a "media circus" around his arrest, as he emerged from a second day of questioning about cash-forhonours allegations.
In a statement, Lord Levy denounced the arrest as "un-necessary, disproportionate and... theatrical" and insisted once more that he was innocent of any wrong-doing.
His comments came as it emerged that officers of the Metropolitan Police's Special-ist Crimes Directorate have interviewed 48 people for their inquiry, 13 of them under caution.
And the officer leading the investigation told MPs that three individuals - understood to be Labour lenders - have refused police requests to be questioned.
The investigation was sparked by allegations that millionaire Labour backers were nominated for peerages in return for making massive loans to the party in the runup to last year's General Election - something the party vehemently denies.
Opposition parties said that Wednesday's arrest of Lord Levy - a close friend and tennis partner of Tony Blair and the Prime Minister's personal envoy to the Middle East - has brought the cash-for-honours scandal to the very door of 10 Downing Street.
But in an 80-minute briefing to the House of Commons Public Administration Committee, deputy assistant commissioner John Yates revealed that his inquiries have covered both main parties and officers have spoken to more Conservatives than Labour people.
He has already submitted two files to the Crown Prosecution Service and expects to continue interviewing witnesses until mid-September before handing over a full report by October.
Mr Yates did not reveal whether he had any plans to interview the Prime Minister himself, but the committee's Labour chairman Tony Wright said: "He didn't seem like a man who would baulk at interviewing anybody."
And he added: "He keeps saying he will go anywhere this investigation leads."
Downing Street said that there had been no approach from the Metropolitan Police to interview Mr Blair.
Asked if Mr Blair retained full confidence in Levy, the PM's official spokesman replied: "Lord Levy remains the Prime Minister's envoy and that speaks for itself."
The committee, which has suspended its own inquiry into the cash-for-honours affair until the police investigation is complete, released a report recommending that all future nominees for peerages should divulge all financial support for political parties, whether it comes in the form of loans or donations.
Mr Wright said that Mr Yates strongly denied suggestions that Lord Levy's arrest was in any way symbolic, insisting it was in fact "integral" to their inquiries.
The senior officer was "very cross" at allegations from former Home Secretary David Blunkett that the Metropolitan Police had been "theatrical" in their handling of the arrest, said Mr Wright.
But this did not deter Lord Levy from releasing a statement through his lawyer Neil O'May expressing his "deep disappointment" that officers chose to arrest him when he attended Colindale Police Station in north London yesterday.
He insisted he was "only too willing" to volunteer any documents sought by police.
The statement said: "This underlines that the arrest was unnecessary, disproportionate and, as has been described by others, entirely theatrical.
"The only result has been a media circus, which has distracted from the issues under consideration. We hope the police will concentrate on the investigation and bring it to a swift conclusion.
"Although any allegations remain unclear, Lord Levy wants everyone to understand that he has not been involved in any wrongdoing or assisted anyone else in any wrongdoing.
"We want to emphasise again that Lord Levy has not been charged with any offence and is confident he never will be."
Lord Levy attended the police station voluntarily, after his questioning was cut short yesterday by a fire nearby.
Mr Wright said that police were "still working on" the people who have declined to answer questions. Investigating officers appear to have obtained "vast quantities" of information, he added.
Mr Wright said he had the impression the police investigation was being taken "very seriously", although it was not clear whether it would lead to charges.