Labour have hailed their win in the Glasgow North East by-election as a dramatic victory and an endorsement of Prime Minister Gordon Brown's policies.
Willie Bain became the constituency's new MP with 12,231 votes - a majority of 8,111 over the SNP.
The Scottish National Party accused Labour of negative campaigning on "grudge and grievance".
Shadow chancellor George Osborne said he did not think the result was "relevant" to the rest of the UK.
The Tory MP said: "Come the general election what we will be looking at is Labour's record in power and Gordon Brown will be the incumbent, and he will be the one who has to explain why he has got so much badly wrong."
The Tories came third in the poll with 1,075 votes and the BNP was fourth.
The Lib Dems came sixth behind Tommy Sheridan of Solidarity.
The contest was sparked by Michael Martin's resignation as Commons Speaker in the wake of the MP expenses scandal.
Voter turnout, at 32.97%, was a record low for a Scottish by-election and 12.8% down on the 2005 General Election.
Speaking at a victory press conference in the constituency on the morning after the poll, Mr Bain said it was a "disastrous" result for Mr Salmond, whose minority SNP administration has run the devolved Scottish government since 2007.
He said: "I think people were very clear that the SNP have not treated Glasgow well on a range of issues from the airport rail link to crime to health to jobs, and it was a disastrous result for him personally.
"He visited this constituency on several occasions and he was soundly rebuffed yesterday."
Scottish Secretary Jim Murphy added: "The people of Scotland are seeing through the SNP, the people of Glasgow have spoken for the whole of Scotland.
"The SNP have got too big for their boots. They've got a little bit arrogant. They get carried away with themselves and they've been brought back down to earth with a bump."
Speaking on BBC Radio Scotland, the Labour MP for East Renfrewshire also claimed Labour's victory was "an endorsement of Gordon Brown and what he is trying to do".
Mr Murphy added: "He visited the constituency, that's not the convention, but he thought it was the right thing to do, to lead from the front of the campaign and he's been vindicated."
Willie Bain - A great night for Scottish Labour
Mr Brown later said: "Willie Bain was a great candidate and will make a great MP. This shows that when we fight hard we win."
SNP candidate David Kerr said the UK government should not read too much into the by-election win.
Speaking at a press conference in Glasgow following the result, SNP depute leader and Deputy First Minister Nicola Sturgeon said: "The SNP campaign did achieve our best Westminster result in Glasgow North East for 35 years, and David Kerr's positive campaign made progress in Labour's safest seat in Scotland.
"But we were clearly disappointed by the result, and one early lesson from this by-election is clear.
"We absolutely must now take Labour's negative campaigning and misrepresentations head on."
She added: "Our challenge is to expose and counteract the dishonest campaigning that has become Labour's trademark.
"Where the SNP offers opportunity, Labour now campaign on grudge and grievance - however inaccurate.
"It is for the SNP now to find a way to deal effectively with these unfounded attacks."
Liberal Democrat Scotland spokesman Alistair Carmichael said: "After 12 years of Labour, the desperately low turnout demonstrates a real lack of enthusiasm for a Labour government that has not delivered for its own core constituency.
"The SNP were identified from day one as the challengers here, but as people see the ever growing list of broken SNP promises at Holyrood they are unable to take advantage of Labour's weakness."
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