Three top City financiers have come to the rescue of the financially stricken Labour Party, making donations totalling £750,000 in May, The Times has learnt.

The donations are meagre compared with the party’s near-£24 million debt but nonetheless they are evidence that not all of Gordon Brown’s so-called high-value donors have fled the party. Labour has become increasingly reliant on trade union funding to keep it afloat.

It is understood that Sir Ronald Cohen, who is a close aide of the Prime Minister and bankrolled his leadership bid, renewed his annual gift of £250,000 in May.

Nigel Doughty, founder of the private equity firm Doughty Hanson, gave the same amount on top of a one-off donation of £14,000 in March.

John Aisbitt, a former Goldman Sachs partner who now sits on the board of Man Group, Britain’s biggest hedge fund manager, also donated £250,000.

The cash injection will help to tide the party over as it faces crippling interest payments on millions of pounds worth of loans. The party has been forced to call in advisers to restructure its debt and agree new repayment terms.

Its loan book currently includes debts to several of the people named in the cash-for-peerages scandal, including Rod Aldridge, the former head of Capita, the outsourcing firm, who resigned after the crisis, Lord Sainsbury of Turville and Sir Gulam Noon, the curry magnate.

Several of its former high-profile donors, including Sir Gerry Robinson, the former chairman of Granada TV, have said they would no longer donate to the party because of its weakened state and because they do not believe that Mr Brown is a fit leader.

A spokesman for the Labour Party last night conceded that it faced a “challenging financial position”. He said that the party’s accounts had been audited and sent to the Electoral Commission, which is due to publish them on July 30.

But the accounts are for 2007 and Labour’s poll ratings have plummeted since then.

According to the Electoral Commission, the party received £3.1 million in donations in the first quarter of 2008, with the majority of those coming from the unions – notably the GMB, Unite and Unison – which are being forced to prop up the party’s coffers until new donors can be found.

Mr Brown has been understandably prickly on the subject of party financing and last week curtly denied that Labour faced bankruptcy.

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