Tory leader and Witney MP David Cameron today urged Prime Minister Gordon Brown to call a General Election in the wake of Labour's disastrous Glasgow East by-election defeat .

He said: "I think we need change in this country."

The loss of Glasgow East at the hands of the SNP will spark panic among the party's MPs and cast fresh doubt over the Prime Minister's future.

The seat had been one of Labour's safest with a majority of more than 13,500, but a massive swing of over 22% saw the nationalists secure it by a margin of 365.

If the performance was repeated at a general election, Mr Brown and a slew of Cabinet ministers would be kicked out of the Commons.