Christopher Moran: So is this the rich donor with a racy past that Cameron is desperate to keep secret?

It's just the sort of rags-to-riches story that David Cameron might have used to inspire his party's faithful as they gathered in Manchester yesterday to hear his message of compassionate conservatism. Christopher Moran was born in modest circumstances in north London, and estimates of his wealth nowadays hover around the £200m mark.

But Mr Cameron made no mention of Mr Moran yesterday - nor is he likely to in the immediate future. Instead, The Independent on Sunday has been told, the party has been desperately trying to conceal his financial support. The property tycoon is said to be one of several secret lenders to whom the Tories paid back a total of £5m to prevent their identities from being revealed last week.

At the time, the party suggested that the hurried repayments on the eve of a deadline set by the Electoral Commission were to honour confidentiality agreements made with the lenders. The truth, insiders suggest, was in most cases to spare the party's own blushes.

Mr Moran made his first million by the age of 21, only to see his reputation ruined when, in 1982, he was expelled from Lloyd's of London, for "discreditable conduct". He was censured by the Stock Exchange four years later and in 1992 fined $2m (£1.15m) in New York for insider dealing.

None of this has stopped him from becoming, by his own reckoning, "astronomically wealthy". He owns the 48,000-acre Glenfiddich sporting estate in Scotland and has a passion for first-growth clarets and the opera. But it is his ownership of Crosby Hall that excites most interest. He bought the freehold to the 15th-century Tudor masterpiece on the banks of the Thames in Chelsea's Cheyne Walk for just £100,000 in 1989. He quickly succeeded in displacing the tenants and has spent an estimated £25m building a 30-bedroom home.

But the project has been far from universally applauded. Public access to the historic marvel - granted under the previous owners - has been denied by Mr Moran, and he lost a High Court battle against his initial architects when they sued for unpaid fees.

It was also the backdrop to the painful breakdown of his marriage to his former wife, Helen, who ran off with a local flower seller in 1998 amid rumours she had been virtually ignored by her husband for years.

The former Mrs Moran said of him, "He doesn't say things in jest - ever. When he wants something he will stop at nothing to get it. He wants people to remember what he has achieved and he's very persuasive - quite ruthless, really."

Despite his fervent support for Conservative principles, successive leaders and treasurers of the Tory party have been wary about accepting cash from the tycoon since Margaret Thatcher. It is thought that John Major flatly turned down the offer of a donation and it is understood that Lord Kalms rejected a renewed offer during his tenure as treasurer under Iain Duncan Smith.

The loophole in funding laws that allows parties to accept cash as loans from undeclared supporters seems to have offered the Tories a chance to take Mr Moran's money without any embarrassment.

If that was indeed their decision it must now be regretted deeply. "They know they screwed up taking Moran's money," one senior Conservative said. "They have been trying desperately to get it back to him so that they won't have to admit to it."

Mr Moran has failed to reply to questions about whether he lent the Conservative Party money.

The party itself has hardly been more forthcoming. "The loans that are repaid are confidential and we won't comment on speculation about the lenders' identity," a spokesman said.

The identity of the secret lenders may yet be forced out of the Conservatives. A senior figure at the Electoral Commission disclosed yesterday that the watchdog has yet to receive a promised list of lenders as well as any details of the loans that have now been repaid.

Until it does so it cannot verify the Conservatives' claims that they were all made on commercial terms. If Mr Moran did make a loan but failed to charge the market rate of interest, he will be named as a donor.

In an irony that won't be lost on those he has done business with, a bout of generosity might land the tycoon in fresh controversy.