The mother of a bankrupt tycoon who donated more than £1 million to the Tories is herself facing financial ruin after she tried to meet her son's debts.

Malcolm Scott's 74 year-old mother Florence faces a sequestration hearing this month after she signed a £10m "personal guarantee" relating to her son's obligations.

Until recently, Scott had the status of being the Conservatives' biggest donor north of the Border.

Through a combination of corporate and personal donations, he poured about £1.6m into the party over the course of a decade.

The grain and property tycoon was also Scottish Tory treasurer and heavily tipped for a peerage.

However, his business empire collapsed earlier this year after he failed to pay back millions of pounds borrowed from banks.

His firms were put into administration after owing over £10m to Societe Generale, Barclays and Lloyds.

He was then sequestrated, the Scottish word for bankruptcy, amid debts of £4m, about £3.7m of which was due to the Bank of Scotland (Ireland) Limited.

Edinburgh law firm Tods Murray LLP was also owed £177,546.

His catastrophic fall appeared complete when his nine-bedroom mansion in Kirknewton – on which he spent more than £2m on gardening – had to be put on the market.

As Scott's businesses began to fall through the floor, his parents tried to help him. His father David, 76, last year signed a "personal guarantee" regarding £10m of his son's obligations, and Florence Scott did likewise in January.

However, according to a legal document lodged at Registers of Scotland, Scott's mother is now facing bankruptcy.

A court date of August 30 has been set at Edinburgh Sheriff Court, at which she can contest the sequestration petition.

Legal documents give the parents' address as a house in Barnton Avenue in Edinburgh.

Last December, ownership of the property transferred from the Scotts to a newly-created firm called Barnton Trustees Ltd. This company then took out a standard security from Investec Bank (Channel Islands) Limited.

The bankruptcy moves comes as creditors and administrators attempt to get to the bottom of how Scott spent his millions, and whether any of it is still left.

Other than funding the Tories, Scott donated generously to the Princes Trust, bought a jet, and purchased lucrative properties, including a hotel in the Courchevel ski resort.

It is also understood he may also have bought a yacht.

According to a report by one of the administrators, Ernst & Young, enquiries are ongoing into the whereabouts of two rugs worth nearly £50,000 and a deal involving the sale of about 18,000 tonnes of barley.

A spokesman for Ernst & Young said: "We're not in a position to provide any further comment at the moment as we believe it may compromise the investigations."

Labour MP Graeme Morrice said: "It is essential that Mr Scott gives a full account of how he spent the millions of pounds lent to him by the banks, and how much is still left. The Scottish Conservatives must also give an assurance that this individual, who allowed David Cameron and William Hague to use his private jet, will play no role in the party until his creditors get their money back."

An SNP spokesperson said: "Another week, another donor headache for the Scottish Tories. Their former treasurer is being pursued for an explanation from creditors and administrators as to what happened to his fortune, and he must co-operate fully.

"But if this is the manner in which he conducts his own personal finances, there are surely serious questions for the Scottish Tories as to how he was conducting their financial affairs."

Neither Malcolm nor Florence Scott could be contacted.

A Scottish Conservative spokesman said: "Malcolm Scott has no role within the party and this is a private matter for him."