Brown snipes could hit Mayor vote, Labour told

The Conservatives today seized on the latest spate of criticism of Mr Brown's premiership to claim that Labour is at war with itself.

Downing Street appeared increasingly alarmed that briefings by former ministers and backbenchers against the Prime Minister could boost Tory mayoral candidate Boris Johnson.

A No 10 source said: "You would think that at a time when every Labour MP and activist is working flat out for the best outcome on 1 May and to re-elect Ken Livingstone, these bitter ex-ministers would join the fight instead of all this anonymous sniping in newspapers."

The latest rumour was that former home secretary Charles Clarke was considering running as a "stalking horse" against him, a move he strongly denied. But the discontent with Mr Brown is more widespread. He faces the threat of revolts over the axing of the 10p starting tax rate and plans to detain terror suspects without charge for up to 42 days.

Mr Livingstone, who will attend Sikh Vaisakhi (New Year) celebrations in London today with Mr Brown, has said he would join the rebellion against the tax shake-up.

The policy has even been criticised by former Treasury minister Geoffrey Robinson, a longstanding Brown ally. Shadow chancellor George Osborne said: "Labour is fighting itself rather than fighting for the country."

Labour is trailing the Tories in the latest poll, by 28 per cent to 44 per cent, a gap which would almost certainly give David Cameron a Commons majority.

The YouGov survey for The Sunday Times also showed Mr Brown's personal ratings plummeting at a more alarming rate than any leader since Neville Chamberlain in the Thirties.

Mr Brown will be pinning his hopes on restoring a sense of leadership when he flies to America tomorrow for meetings with President Bush and other leaders at the UN. Health Secretary Alan Johnson insisted he was "a serious man for serious times".