Miliband hails Labour win in Feltham and Heston
Labour leader Ed Miliband says his party's victory in the Feltham and Heston by-election is "a verdict on the government's failed economic plan".
Winning candidate Seema Malhotra secured victory in the west London seat with an increased majority of 6,203 over the Tories, a swing of 8.6%.
The Lib Dems held on to third place with 1,364 votes, fighting off UK Independence Party challenge.
Turnout was just 28.8% - the lowest in a by-election for 11 years.
The previous lowest was in West Bromwich West in November 2000 at 27.6%.
The by-election was prompted by the death last month of Labour MP Alan Keen.
'Better way forward
Visiting the constituency with Ms Malhotra and Labour's London Mayoral candidate Ken Livingstone, Mr Miliband said: "This by-election offers a verdict on the government's failed economic plan.
"It's the verdict of young people in Feltham and Heston looking for a job. It's the verdict of people who are seeing their living standards squeezed.
"It's a verdict that says we can't go on with the idea that there is no alternative. It's a verdict that says there is a better way forward."
He said Labour had more to do to win back voters whose trust was lost during its time in office, but the victory showed a swing "from Conservative ideas to Labour ideas".
Mr Miliband said it was "offensive" of the Conservatives to dismiss the result as inevitable.
Ms Malhotra grew up in Feltham, and went to school in Heston. She was an adviser to Harriet Harman during her stint as Leader of the Opposition in 2010.
Labour polled a total of 12,639 votes.
Conservative chairman Baroness Warsi said the result was "disappointing" for her party, although not unexpected.
But she said the very low turnout was "deeply worrying": "By-elections generally have low turnouts, [especially] by-elections at this time of year when it's cold and just before Christmas and people are thinking about other things.
"But I am concerned about the level of political engagement. It can't be right that on 12,000 votes a constituency can be won."
The Conservatives' share of the vote was down from 33% to 28%, while the Lib Dems dropped from 14% to less than 6%.
UKIP saw its share more than double from 2% to more than 5% - polling 1,276 votes - but it was unable to take third place from the Lib Dems.
The party - which campaigns for the UK to leave the European Union - said its chances had been damaged by Prime Minister David Cameron's decision to veto an EU-wide treaty at last week Brussels summit, which it believes gave the Tories a boost in the final week of the campaign.
Deputy Lib Dem leader Simon Hughes said the result was as expected.
"What happened here was what normally happens in a by-election. People protest against the government, so government parties take a hit [and] the opposition normally moves forward."
He said his party was "fighting a particularly difficult corner" because it was pro-European in a country "where the majority of people still like to see us, as it were, having a go at our European neighbours".
UKIP leader Nigel Farage said the Lib Dems were "almost a busted flush".
Feltham and Heston was won by the Conservatives in 1983 and 1987 during Margaret Thatcher's premiership.
At the last general election Labour's majority in the seat, located to the west of London, was cut to 4,658 in a 4.8% swing to the Conservatives.
All the three main party leaders visited the constituency during campaigning for what is the sixth by-election during this Parliament.
The full results were:
- Seema Malhotra, Labour - 12,639 (54.42%, +10.79%)
- Mark Bowen, Conservative - 6,436 (27.71%, -6.32%)
- Roger Crouch, Liberal Democrats - 1,364 (5.87%, -7.87%)
- Andrew Charalambous, UKIP - 1,276 (5.49%, +3.45%)
- David Furness, BNP - 540 (2.33%, -1.21%)
- Daniel Goldsmith, Green - 426 (1.83%, +0.74%)
- Roger Cooper, English Democrats - 322 (1.39%)
- George Hallam, London People Before Profit - 128 (0.55%)
- David Bishop, Bus-Pass Elvis Party - 93 (0.40%)