George Galloway has scored a dramatic victory in the Bradford West by-election

George Galloway has scored a dramatic victory in the Bradford West by-election, securing a 10,000-plus majority in what he called a "massive rejection" of mainstream parties. 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 on Thursday, 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. And 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. He said: "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."