Gordon Brown has vowed to carry on despite suffering a humiliating by-election defeat.

Labour saw its third safest seat in Scotland, Glasgow East, fall to the Scottish National Party (SNP) after a massive 22 per cent swing.

The SNP's John Mason, beat Labour by 365 votes. The Conservatives' share of the vote also fell while the Liberal Democrats were beaten into third place and candidate Ian Robertson lost his deposit.

Mr Mason said: "This SNP victory is not just a political earthquake, it is off the Richter scale. It is an epic win, and the tremors are being felt all the way to Downing Street"

SNP leader Alex Salmond said: "We have now demonstrated that there are no safe seats for the Labour Party anywhere in Scotland."

Tory leader David Cameron urged the Prime Minister to call a general election in the wake of the defeat.

Annabel Goldie, the leader of the Conservatives in Scotland, said the result represented the "abject humiliation of Labour" and the "evaporation of the Liberal Democrats as a meaningful force in Scottish politics".

But Mr Brown ruled out a general election, saying he was "just getting on with the job".

He added: "My full focus is on taking people through these difficult times."

Speaking in the Commons, defence secretary Des Browne paid tribute to defeated Labour candidate Margaret Curran, who he said had "paid the price" of a national mood of anger at the rising cost of living.

Unite general secretary Tony Woodley said the Government should target "greedy oil companies" to ensure basic living costs are brought down.

He said: "It's time for intervention, intervention, intervention by the Labour Party.

"This Government has got to act and they have got to act in favour of working men and women in this country."