Tony Blair's official spokesman dismissed allegations that the government is threatening to reveal damaging details of the former minister's business dealings if he publishes an autobiography.

The former paymaster general is planning to give his side of the home loan scandal in his memoirs The Unconventional Minister.

But the spokesman said the suggestion Mr Blair's aides could manipulate the findings or presentation of a forthcoming inquiry into Mr Robinson's business dealings was "all wrong".

He said: "Officials couldn't influence a DTI report even if they wanted to. It's not just something that's improper - it's impossible."

Ian Pearson, Mr Robinson's parliamentary aide while he was in office, also said it was inconceivable Downing Street was behind the rumours.

He said: "I don't believe these stories are really coming out of Downing Street at all.

"Geoffrey served as a minister at the prime minister's pleasure and I think he did a good job while he was there.

"I think he now wants to set the record straight."

The fuss that ensued when it emerged Mr Robinson had secretly lent £373,000 to then trade secretary Peter Mandelson cost both men their jobs.

Peter Mandelson has returned to the cabinet

Mr Mandelson recently returned to the cabinet as Northern Ireland secretary and makes his first appearance back at the despatch box on Wednesday.

But Mr Robinson has complained he has been continually treated as a "non-person" since he quit.

Tories had targeted the former paymaster general for months before his resignation, claiming irregularities in the business affairs of the millionaire.

The Department of Trade had already begun an investigation into allegations of breaches of company law when the home loan scandal broke - it has not yet been published.

As well as fresh disclosures about his saga, Mr Robinson is believed to be planning to publish an account of how he was approached to help fund a blind trust for Tony Blair's office before the 1997 election.

He has informed a newspaper that a senior aide of the prime minister approached him to ask for more than £200,000.

Under Labour Party rules, the leader and his aides are not supposed to know the names of donors to blind trusts.

The prime minister's spokesman said he had "no idea who contributed to the blind trust".

He added: "It is not secret Geoffrey Robinson, who is both a wealthy and generous man, has given donations to the Labour Party."

Mirror Chief Political Correspondent Paul Routledge: "I hope he ignores this blackmail"

Paul Routledge, the author of the book revealing Mr Robinson's loan to Mr Mandelson, said he hoped the autobiography would still be published.

Mr Routledge, who is The Mirror's chief political correspondent, said: "Geoffrey Robinson must be the first politician to be vilified for giving money away rather than taking it in brown envelopes, but I think his generosity again may be his undoing.

"I hope he ignores this blackmail and goes ahead with the book because we all want to see what's in it.