British Prime Minister Gordon Brown lost his fourth minister within 24 hours on Wednesday as he faced taunts that his government was in meltdown on the eve of polls which could seal his fate. Amid talk that the wave of resignations may be the beginning of the end of his premiership, Brown faced a rowdy Prime Minister's Questions session at which Conservative leader David Cameron urged a snap general election. "The government is collapsing before our eyes," said Cameron, tipped by opinion polls to be elected as premier within a year. "Why doesn't he take the one act of authority left to him: get down to the palace, ask for a dissolution (of parliament), call that election?" Nick Clegg -- leader of the second opposition Liberal Democrats -- said Brown's Labour Party was "in total meltdown".