The Conservatives immediately called for a Department of Trade and Industry investigation into Mr Robinson's business affairs. Angela Browning, the shadow trade and industry secretary, said: "This latest development is outrageous. It is becoming increasingly apparent that Mr Robinson's business dealings don't bear scrutiny.
"Clearly this is new evidence that suggests the DTI must meticulously investigate Mr Rob- inson's dealings in TransTec."
The latest twist in the tale came when Roger Carr, the chief executive brought in by Mr Robinson to run TransTec while he concentrated on his political career, and Bill Jeffrey, who until recently was the finance director, both resigned on Christmas Eve. TransTec, which admitted three months ago it was in trouble with its lenders, said it would be selling off all its trading subsidiaries. The group took out a pounds 70m loan with HSBC, the banking group, and is struggling to pay back the money.
TransTec's shares were sus- pended at 6.5p following the announcement, valuing the stake held in the company by Robinson family trusts at just pounds 1.98m. At their peak this stake was worth more than pounds 35m.
A statement issued with the resignations said that Mr Carr and Mr Jeffrey had failed to tell the rest of the board, the auditors or the group's financial advisers of an $18m (pounds 11.2m) claim by an American customer.
The claim has been in existence for more than two years and $12m of it has been paid, though part of this payment was hidden by charging it as "tooling expenditure" and making it a write-off on the balance sheet. The group is in talks with the customer about the $6m.
Colin Cooke, chairman of TransTec, said that it had asked its auditors, Pricewaterhouse- Coopers, to investigate the circumstances of the claim to see whether it should have been disclosed in previous accounts.
The collapse in the value of TransTec shares has rounded off a terrible year in which both Mr Robinson's political career and his personal fortune have been cruelly cut down. On the day before Christmas Eve last year, Mr Robinson resigned from his post as Paymaster General over revelations about a pounds 373,000 loan made by him to Peter Mandelson, then the trade and industry secretary. Mr Mandelson resigned too. Mr Mandelson has now been re-admitted to the Cabinet as Northern Ireland Secretary, but Mr Robinson is still in the wilderness.
At the same time Mr Robinson's personal fortune, built up largely though his work at Jaguar Cars and once put at nearly pounds 50m, has shrunk and he is now said to be worth less than pounds 10m. This is less than the pounds 12.75m that he inherited from Joska Bourgeois, the Belgian entrepreneur.
He does still own the villa in Tuscany which he lent to the Blair family for a summer holiday, as well as two homes in Britain and a flat in Cannes.
TransTec was created by Mr Robinson in a deal with the late Robert Maxwell. The publishing tycoon paid pounds 5.5m to Mr Robinson for his businesses, and absorbed them into a group called Central & Sherwood, which was renamed TransTec.
Mr Robinson's business dealings with Maxwell have been the subject of much controversy and only last week it emerged that he will not now face action by the DTI over irregularities at Hollis Industries, a Maxwell company where Mr Robinson had been chairman.
Mr Robinson was unavailable for comment before Christmas.