George Galloway video exclusive: My vision for a new Bradford

Respect swept from fifth place at the 2010 general election to a commanding victory for the ex-Labour anti-war campaigner against his former party on a swing of 36.59%.

It was “the most sensational result in British by-election history bar none”, he said on stage after being declared the victor with well over half the total votes.

The reverse is a serious blow for Labour which entered polling day as overwhelming favourite to retain the seat at the end of a fraught week for the Government.

Instead, it became the first Opposition party to slump to defeat in a mid-term poll since the Liberal Democrats took Romsey from the Tories in 2000.

Party sources pointed to a massive slump in the Conservative vote as evidence of the Government’s unpopularity. The Liberal Democrats lost their deposit.

But the scale of the turnaround, in a seat the party had held since 1974, is bound to raise further questions about the leadership of Ed Miliband.

Mr Galloway won 18,341 votes to the 8,201 for Labour candidate Imran Hussain.

Labour went into the contest - sparked by the resignation due to ill-health of Marsha Singh - the overwhelming favourites with bookmakers.

Some had closed their books yesterday, however, after receiving a late flurry of large bets that Mr Galloway would cause a serious upset.

As he did in the 2005 general election, when he dramatically swiped an east London seat from his former party, Mr Galloway targeted the votes of a large Asian community.

Turnout in the poll was just over 50% - considered high for such a contest, especially in an urban area.

Mr Galloway told Sky News he had won a “big victory” - winning at least 50% of the vote in some areas and doing well in areas without large Muslim populations.

Unlike after his 2005 election victory in Bethnal Green and Bow, where he had said he would serve only one term, he said he hoped to be MP for Bradford for the long term.

“It is a very comprehensive defeat for New Labour, it is a pathetic performance by the Government parties.

“The big three political parties have had a very salutary, unkind lesson this evening and I hope that they all take note.

“The people of Bradford have spoken this evening for people in inner cities everywhere in the United Kingdom.”

Labour MP Toby Perkins said the result was “desperately disappointing”, but pinned Mr Galloway’s success partly on his celebrity status from having appeared on a television reality show.

Mr Perkins conceded, however, that his party had lessons to learn from the way Mr Galloway had been able to “capture the mood” of the electorate, especially young people.

He said: “I think his celebrity was a very significant factor. There was a great deal of people, who in this city, voted for the Labour Party 18 months ago. A tiny number at that time were voting for Respect. Now since then, we have seen the Labour Party get more popular in the national polls, yet in the space of three weeks George Galloway was clearly able to capture the mood, particularly of the younger voters.

“We need to learn from that. It’s a desperately disappointing result for us. Bradford is an important city for the party and it has come as a big shock the way that things have changed over the past few weeks.”

He went on: “I think frankly there wasn’t a lot the other parties could do about it. They’d seen him on Big Brother.

“They wanted him on their streets and now they’ve got it, and let’s hope that he lives up to the promise that he’s made to them and actually delivers on the optimism that surrounds his campaign, which hasn’t always been the experience of constituents who have had George Galloway as their MP in the past.”

Labour’s candidate did not make a speech following the announcement of the results and was quick to leave the stage.

As a jubilant Mr Galloway left the sports hall he was mobbed by his supporters and had to retreat back into the building.

As he left again he was hoisted onto the shoulders of supporters as people chanted “Respect”, while others said: “We love you George.”

Mr Galloway was carried around the side of the building as his supporters continued to chant and cheer.

The Liberal Democrats said they were “clearly disappointed” with the poor showing, but blamed the lost deposit on the unexpectedly high turnout.

“We had a great hard-working candidate and dedicated team, but sadly didn’t manage to break through,” a spokesman said.

“If turnout had been as expected we believe we would have fared much better, but the Galloway factor brought out thousands of extra voters, hitting all of the three main parties.

“While we were always expecting to fight for fourth in this election, it is quite astonishing for Labour to lose this seat and the Conservatives see such a drop.”

The swing of 36.59% against Labour was one of the highest recorded in recent decades, but short of the post-war record of 44% achieved by Lib Dem Simon Hughes in Bermondsey in 1983.