Former MP Harvey Proctor has refused to give evidence to a review of Scotland Yard's handling of historical sex abuse probes, which he claims will be "a whitewash".
The 69-year-old declined an invitation to meet the former High Court judge leading the inquiry on May 12, because he alleges that the investigation will not be independent.
In a letter to Louise Oakley, a lawyer assisting Sir Richard Henriques with the probe, Mr Proctor said: "You are participating in a secret inquiry which is a cover-up and destined to become a 'brilliant' whitewash."
The ex-Tory politician, who represented Basildon from 1979 to 1983 and Billericay from 1983 to 1987, saw his home raided and was twice interviewed under caution as part of a doomed Scotland Yard investigation into claims of a Westminster paedophile ring.
He furiously denied any involvement and was finally told in March that he would face no further action.
The £1.8 million, 16-month Operation Midland, which looked at claims that boys were sexually abused by a number of public figures more than 30 years ago, ended earlier this year without a single arrest.
Mr Proctor has refused to meet Sir Richard, partly because the retired judge wrote a separate, damning report for the Crown Prosecution Service on missed chances to prosecute the late Lord Janner, who was also investigated as part of Operation Midland.
According to The Sunday Times, Lord Janner's family are also refusing to co-operate with the Henriques review.
Metropolitan Police Commissioner Sir Bernard Hogan-Howe announced in February that he had called in Sir Richard to examine a number of investigations involving non-recent abuse claims against public figures.
It came amid fierce criticism of Operation Midland, which saw raids on the homes of 92-year-old D-Day veteran Lord Bramall and the late Lord Brittan.
Scotland Yard will only publish parts of Sir Richard's final report, but a full copy will be given to the Goddard Inquiry into child sexual abuse.
Mr Proctor said he will also decline to give evidence to the public inquiry, and is willing to face prison or a fine if he is compelled to do so.
He said: "She (Dame Lowell Goddard) will have to fine or imprison me because there is no way I'm appearing before her. Her inquiry is biased and it's pro-victim and survivors. The assumption is that it was all credible and true."
In April Justice Goddard made a statement defending the inquiry, saying: "All of our investigations will be approached with diligence and with objectivity. In every single instance, I will ensure the inquiry examines all of the issues fairly and impartially.
"I am committed to ensuring that we hear all relevant testimony, including from victims and survivors as well as from those affected by false allegations of abuse."