Live blogging on the latest rebellion rumours

A former Labour minister has added to the growing pressure on Gordon Brown by claiming he is the least popular British Prime Minister since Neville Chamberlain made a doomed bid to appease Adolf Hitler.

George Howarth’s barbed comparison came just hours after David Cairns, a minister in the Scotland Office, resigned from the Government, leaving the Labour hierarchy braced for further challenges from within the party.

Mr Howarth, MP for Knowsley North and Sefton East, said Mr Brown was more unpopular than any leader “since Neville Chamberlain after Hitler invaded Norway” in 1940, adding: “We can’t allow that situation to continue.”

Mr Brown’s spokesman told reporters this morning that the Prime Minister was too busy to consider such claims: “The PM is not giving these matters a moment’s thought," he said.

Mr Howarth admitted that the timing of the leadership challenge was appalling, as the global financial markets shuddered in response to the banking crisis, but insisted that change at the top of Labour was necessary.

“The reality of the situation is that the timing wasn’t of our making," he said.

"I didn’t leak the letters that said we wanted a leadership contest. Others who did that may have to answer for their actions at some point in the future,” he told the BBC's Newsnight programme, denying that there was a specific plot to unseat Mr Brown and install a Cabinet rival.

Yesterday, however, saw the resignation of a second member of the Brown Government. Mr Cairns followed Siobhain McDonagh, an assistant whip, in quitting and calling for the Prime Minister to initiate a leadership contest.

Mr Cairns told Mr Brown in a letter of resignation that the time had come “to take the bull by the horns and allow a leadership debate to run its course”.

He added: “I know that it is incompatible to hold this view and to remain a serving minister, and although it had not been my intention to resign, I have reluctantly concluded that it is the only honourable course of action left open.”

Jack Straw, the Justice Secretary, was among a series of party heavyweights who emerged from yesterday’s Cabinet meeting to give his backing to the struggling Prime Minister.

Times Recommends

• The bright side of this winter rain
• Story behind the picture: Snow Leopard, 2008
• Times Charity Appeal: The Place2Be