Senior ministers have rallied round Gordon Brown after he suffered the humiliation of another catastrophic by-election defeat for Labour.

Following the dramatic loss of Glasgow East - Labour’s third safest seat in Scotland and 25th safest in Britain - Cabinet ministers rejected claims that it was time for a change at the top of the Government.

However one Labour MP publicly called for a leadership contest while others warned that the Government must change direction if it was to stand any chance of holding on to power at the next General Election.

The result - finally announced at 2.30am after Labour demanded a recount - represented a stunning victory for the Scottish National Party who overturned a 13,507 Labour majority to take the seat by a margin of 365 votes.

SNP leader Alex Salmond said there was no longer a single Labour seat anywhere in the country which could be considered safe, while Tory leader David Cameron challenged Mr Brown to call a General Election.

The Prime Minister, attending Labour’s National Policy Forum at the Warwick University campus in Coventry, brushed off suggestions that he should go to the country or that his leadership was under threat.

But coming after the loss of Crewe and Nantwich, Labour’s humiliating fifth place at Henley-on-Thames, and the party’s drubbing in the May local government elections, the result was another body blow to his authority.

Labour backbencher Graham Stringer said it was now up to members of the Cabinet to tell Mr Brown that the Government could not carry on as it was and, if necessary, force the issue by challenging him in a leadership contest.

“It really requires members of the Cabinet to have a closed and honest discussion with Gordon Brown,” he said. “We need a new start and that can only come from a debate around the leadership. I hope those discussions will take place.

“It really is a question of whether the Labour Party has the will to win the next General Election.”

Labour peer Lord Desai said that it was like “watching a crash in slow motion”. He did not believe the party had the “stomach” for a leadership challenge and urged Mr Brown to stand aside instead.

“He has to admit that he is the problem and he has to remove himself. Nobody else is going to challenge a sitting leader because that is too expensive and too damaging a process for the party,” he said.

Mr Stringer said the public support for Mr Brown by ministers did not reflect the private discussions which had been taking place among Labour MPs “at all levels” in the party.

However the chairman of the Parliamentary Labour Party, Tony Lloyd, insisted that there were “very few voices” in the party who wanted a change of leadership.

“The answer to this isn’t looking for Gordon Brown’s scalp,” he said.

Communities Secretary Hazel Blears acknowledged that it had been a “very bad result” but insisted that it did not mean it was time for a change at the top.

“The easy thing to do in times that are tough - and times are tough - is for a party to cut and run. That’s not the Labour Party and that’s not Gordon Brown,” she said. “Changing faces at the top of the party is not what people expect us to do.”