Defiant Prime Minister Gordon Brown has brushed off calls to quit following the resignations of four ministers in 24 hours. Tory leader David Cameron taunted Mr Brown in the Commons, saying his command over his Cabinet had "simply disappeared", and urge him to "get down to the Palace, ask for a dissolution, call an election". Mr Cameron accused the premier of being "in denial" in the wake of the resignation of Communities Secretary Hazel Blears and other ministerial departures. And Liberal Democrat leader Nick Clegg said the Government is in "total meltdown" although Mr Brown insisted he is dealing with the problems facing the country. Meanwhile, rumours are sweeping Westminster of rebel Labour MPs gathering signatures from backbenchers for a letter to Mr Brown, calling on him to step down. The Guardian's website says MPs are being given an email address to which they can send their endorsement of the "Gordon must go" call, which could be handed to the PM on Monday after results are declared in the council and European polls. At Prime Minister's Questions, Mr Cameron seized on Mr Brown's problems saying: "This morning the Communities Secretary resigned from the Cabinet. This follows yesterday's announcement that the schools minister is standing down, the minister for the Cabinet Office is leaving and the Home Secretary is resigning. "Why doesn't the Prime Minister accept that his ability to command his Cabinet has simply disappeared?" Mr Brown shrugged off the jibe and instead praised Ms Blears and Home Secretary Jacqui Smith, saying: "At a time like this the House should come together to acknowledge contributions that have been made in the public interest." Ms Blears' departure came hot on the heels of the resignation of Ms Smith, who confirmed she will quit in the coming reshuffle, expected within the next few days. She had come under pressure after it was revealed she did not pay capital gains tax when selling a property on which she had claimed the parliamentary second homes allowance. She later repaid £13,000 to HM Revenue and Customs. In a statement, Ms Blears urged voters to back Labour in the Euro-elections and said she wanted to "return to the grassroots where I began, to political activism, to the cut and thrust of political debate". "Today I have told the Prime Minister that I am resigning from the Government. My politics has always been rooted in the belief that ordinary people are capable of extraordinary things, given the right support and encouragement." She continued: "The role of a progressive Government should be to pass power to the people. I've never sought high office for the sake of it, or for what I can gain, but for what I can achieve for the people I represent and serve. "In this next phase of my political life I am redoubling my efforts to speak up for the people of Salford as their Member of Parliament. I am returning to the grassroots (where I began), to political activism, to the cut and thrust of political debate. "Most of all I want to help the Labour Party to reconnect with the British people, to remind them that our values are their values, that their hopes and dreams are ours too. "I am glad to be going home to the people who matter the most to me: the people of Salford. Finally, there's an important set of elections tomorrow. My message is simple: get out and vote Labour."