Gordon Brown hailed Labour's victory in the Glenrothes by-election as a vote of confidence for Labour's response to the economic downturn.
 
The Prime Minister said: "What I have learned from this by-election is that people are prepared to support Governments that will help people through the downturn and offer real help to people.
 
"They are less willing to support people who have no idea about how to solve the problems we have got."
 
Lindsay Roy was elected the new MP with a majority of 6,737 over the SNP's Peter Grant. The SNP had repeatedly predicted they would win the seat. With Alex Salmond saying only last week: “Yes, we can win and, yes, we will win the Glenrothes by-election.”
 
The by-election in the Fife constituency was held after the death of Labour MP John MacDougall.
 
An appalling night for David Cameron's Conservatives saw the Tories come a poor third with 1,381 votes while the Lib Dems polled 947 votes.
 
Deputy Leader Harriet Harman said, "Our campaign was true to Labour's values of defending older people from unfair cuts and increased charges in home help services.
 
"Congratulations to our new MP Lindsay Roy, campaign manager Gordon Burns and Jim Murphy. I would also like to thank all the hard working party staff and members from across the country who helped in the campaign."
 
Scottish Secretary Jim Murphy said: "It's the first time since the 1970s that Labour in a seat that it's held has actually increased its share of the vote in a by-election. So it's an historic night in that sense.
 
"The main reason would be that we had a Prime Minister who personally campaigned in the constituency, there's a great appreciation for the work that Gordon is doing and will continue to do.
 
"There's also a demand by the voters to see which of the parties has an answer to the big questions. The Labour Party under Gordon's leadership has answers to these big and difficult economic questions."