According to a report in a Sunday paper, the Smith Political Economy Unit - set up by a close aide of Mr Brown - received almost £200,000 from Mr Robinson.

Gordon Brown: Believed to have fought to save Mr Robinson

The present Chancellor used the think-tank to research policies into the Windfall Tax and Labour's economic policies, as well as paying for expert advice on how they could be put in place.

The Treasury reacted furiously to the suggestion in Sunday's Observer newspaper that Mr Robinson gave the money to Mr Brown, although it did not deny that Mr Robinson had paid large amounts of money into the unit.

A Treasury source is reported to have said that the story was "misleading and completely wrong", and that Mr Brown received no money from the fund.

'No conflict of interest'

The source said: "Mr Brown enjoyed no personal financial gain or loan. There has never been any issue of conflict of interest arising and throughout he has acted in accordance to House of Commons rules."

Despite the denials of any wrongdoing the funding question could embarrass the Chancellor who is also facing claims that his press aide Charlie Whelan leaked the story about Trade and Industry Secretary Peter Mandelson's £373,000 home loan which also came from Mr Robinson.

Peter Mandelson: Mr Robinson loaned him nearly £400,000

Mr Brown is believed to have fought bitterly to save Mr Robinson when the allegations mounted against him shortly before Christmas and Prime Minister Tony Blair suggested he should resign.

According to The Observer, Mr Robinson was the main, if not the sole donor, to the non-profit-making Smith Political Economy Unit.

The think-tank received donations of £208,500 in the first year of its existence. It spent £144,000 on research costs and £46,000 on legal and professional fees.

The unit ceased business in 1997, the newspaper said. The company's stated purpose was to "advance the education of the public in the field of study and research into the political economy of the UK".