BBC Correspondent Carolyn Quinn looks at the allegations surrounding Peter Mandelson

Mr Mandelson said he had been given a "stiff kicking" by "mischievous" newspapers - but had not needed to declare the loan, which he put towards buying a home, as it was "a personal arrangement".

But opposition Conservative MPs have criticised the loan and demanded more details and a full inquiry.

Peter Mandelson: "There is no conflict of interest"

Mr Mandelson paid £475,000 for the house in west London's fashionable Notting Hill district more than two years ago while in opposition.

After the trade secretary was appointed to his current post in the summer, he was informed the Department of Trade and Industry would be investigating Mr Robinson's financial dealings.

But it was agreed Mr Mandelson and other ministerial colleagues should play no part in the inquiry.

Peter Mandelson: "I have done nothing wrong"

Tony Blair's official spokesman said the matter was considered closed after it had been looked into by the Cabinet Secretary Sir Richard Wilson.

The spokesman said he was satisfied Mr Mandelson had properly "insulated himself" from an investigation by his DTI officials into Mr Robinson's business affairs.

Peter Mandelson's home cost £475,000

He said Mr Mandelson would now be writing to the new Registrar for Members Interests inviting her to rule on whether he had breached Commons rules by not declaring the loan.

Mr Mandelson said the outstanding amount was £332,000. He paid interest at a base rate and hoped to finish paying it all off soon.

The minister said he did not believe Mr Robinson had any "ulterior motive" or "political motivation" in helping him with the loan.

He said: "If I had felt he was inappropriate I, of course, wouldn't have accepted it."

Geoffrey Robinson has been criticised over his offshore trusts

He went on to describe himself and Mr Robinson as "exotic" personalities who attract attention.

Mr Blair found out about the loan last week and asked Cabinet Secretary Richard Wilson to investigate whether there was a conflict of interest

Downing Street said ministerial code only required ministers to ensure they were not placed in a situation where they might be facing a conflict of interest.

John Redwood wants further examination of the loan

But Trade and Industry shadow John Redwood said: "We need a lot more information.

"We need to know from Mr Mandelson what the terms of the loan were.

"This is a huge amount of money, way outside the sum of money you would normally lend to an MP on a parliamentary salary and we need to know what strings were attached."

Malcolm Bruce thinks there are questions to be answered

Liberal Democrat Treasury spokesman Malcolm Bruce described the disclosures as "disturbing" and said Mr Mandelson should have "flagged up the potential conflict of interest" as soon as he was notified of an investigation into Mr Robinson's affairs.

Labour backbencher Diane Abbott said she was "baffled" Mr Mandelson had needed such a large loan as MPs with constituencies outside London receive grants to help them buy or rent properties in the capital.

She said: "He argues that he did not reveal this sizeable loan to his officials and he didn't declare it in the register of MPs' interests because he did not see that there was a conflict of interest.