One of Britain’s largest unions announced plans yesterday to suspend funding to Labour MPs after its leader launched a savage attack on the party.

Dave Prentis, general secretary of Unison, which is also the Labour Party’s second-largest donor, said his members were “tired of feeding the hand that bites them”, as he declared that public sector support for the Labour Party had collapsed.

Addressing delegates at Unison’s annual conference in Brighton Mr Prentis suggested that the union’s £1 million campaign fund to support the party at the next general election was also under threat unless it changed tack on policy.

Mr Prentis said there would be no more blank cheques as he said Labour in office “had let the billionaires, the bankers and the private profiteers call the shots”.

The party is already in debt and heavily dependent on its union donations so any withdrawal of cash would have severe repercussions for Labour’s general election funds.

Unison donates roughly £1.5 million annually to the Labour Party plus £1,500 each to the local parties of the 64 Labour MPs it supports. In addition it provides £1 million for campaign literature and staffing at general elections.

Mr Prentis received a standing ovation from delegates as he told them to stop supporting local Labour parties. “Our Labour link is an integral part of our union. But our members are tired of feeding the hand that bites them. No more blank cheques.”

He said in future money would go only to support MPs who stood up for the union’s values on public services, such as opposing privatisation and competitive tendering. Mr Prentis cited a MORI poll commissioned by Unison last weekend that had shown that only 30 per cent of public sector workers backed Labour.

As Unison turned its fire on Labour, the Prime Minister tried to respond, urging both trade unionists and Labour supporters to fight “like never before” to save public services.

Addressing the annual conference of the GMB union in Blackpool, Gordon Brown highlighted extra spending on the NHS, education and other areas since Labour came to power in 1997 and warned of cuts if a Tory government was elected.

Simon Lewis, a public relations expert who was hired by Buckingham Palace to improve the Queen’s image after the death of Diana, Princess of Wales, has been appointed by 10 Downing Street to help to improve Mr Brown’s standing.

Mr Lewis moves from the private sector to become one of the country’s most powerful civil servants, serving as Mr Brown’s communications chief and official spokesman, with a general election less than a year away.

Mr Lewis has known Mr Brown and his wife, Sarah, for several years. He is understood to have been the first choice of Mr Brown and Lord Mandelson, who also knows him well, when Michael Ellam, the current communications head, told the Prime Minister in April that he wanted to return to the Treasury in the summer.

The arrival will mean another shake-up in Mr Brown’s campaigning operation, with Mr Lewis the second senior figure after Stephen Carter to be recruited from public relations. Lord Carter of Barnes is Communications Minister but will step down soon.

Mr Lewis joined Buckingham Palace in 1998 to devise a PR strategy for the Royal Family after the death of Diana. Regarded as an effective operator, he had political experience as head of communications at the old Social Democratic Party. His brother William edits The Daily Telegraph.

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