Bristows, the company providing the helicopters, including a Sikorsky for the Prime Minister and two Pumas, insist they are not doing it as a donation to the Tory party.
A Conservative spokesman said: "It is not a donation by Bristows. It is expected that the total cost for the six-week campaign of the helicopter bill will come to pounds 20,000."
A British Midlands 737 jet which Mr Major used to fly to Manchester yesterday is being provided by British Midland, whose chairman, Sir Michael Bishop, is a party supporter. Sir Michael accompanied John Major on his visit last week to the Scottish Borders and is believed to be a substantial private donor.
Gore Vidal, the American novelist and veteran White House observer, said the Conservative Party's election campaign funds were the biggest mystery of the campaign.
The Tories have reversed a pounds 19m deficit and are expected to spend at least pounds 20m on their campaign. The Tory party chairman, Brian Mawhinney, has laughed off reports that he has a war chest of pounds 40m but it is likely that the total sums raised amount to pounds 40m, including wiping out the debt.
Much of that transformation may be due to anonymous overseas backers who in the past have included such figures as Azil Nadir, the discredited former head of Poly Peck, now a fugitive in northern Cyprus.
Tony Blair, the Labour leader, has promised to ask the Nolan Committee to investigate party funding if Labour is elected, in order to clean out the political stables in Britain.
Mr Major has refused to match the Labour leader's promise and has attacked Mr Blair for hypocrisy in operating with a blind trust to hide the names of donors to his private office.
Labour will divulge the names of any sponsors donating more than pounds 5,000 to party funds.
In this election, the Tory party is receiving pounds 7,000 per head from newspapers and broadcasting journalists for daily travel costs. But the names of the big backers are unlikely to be declared. They may include Lord Forte, listed at the weekend as the equal 58th-richest man in Britain, with an estimated fortune of pounds 275m after the hostile take-over by Granada for his family-hotel business.
After Baroness Thatcher went to Conservative Central Office to address the troops on Sunday, a black Rolls-Royce drew up and Lord Forte slipped inside barely noticed.
And that is how the donors like it.Reuse content