British election upset puts big beasts to the slaughter

* Labour's would-be finance minister Ed Balls loses seat

* Veteran Liberal Democrats sent packing

By Michael Holden and Kate Holton

LONDON, May 8 (Reuters) - Victory by David Cameron's Conservatives on Friday in one of the most unexpected upsets in British political history has been accompanied by an almost unprecedented electoral bloodbath of dozens of high-profile figures.

Within hours of Cameron securing a majority in defiance of all forecasts, the leaders of three of the other major parties all quit after voters decisively rejected their policies at the polls.

And when British lawmakers return to parliament, many of their best-known former colleagues will be absent, victims of some astonishing voting swings.

"I take absolute and total responsibility for the result and our defeat at this election. I'm so sorry for all of those colleagues who lost their seats," Ed Miliband, leader of the main opposition Labour Party, said in his resignation speech.

Labour had hoped to form the next government, with Miliband as prime minister, after all opinion polls wrongly suggested they were level with the Conservatives.

In the end, they were battered in England by the Conservatives and humiliatingly hammered in their traditional heartlands in Scotland after a staggering swing to the Scottish National Party, losing all but one of the 41 seats there.

Their national election chief in Scotland even lost his seat to a 20-year-old political novice.

Despite his party's awful showing, Miliband retained a sense of humour, thanking the public for the "most unlikely cult of the 21st century, Milifandom" - a Twitter trend which attracted hundreds of young, mostly female, Britons who declared their love for him.

However, laughs were few and far between at the headquarters of the Liberal Democrats, junior partners in Cameron's previous coalition government who were almost annihilated as they paid the price for some of its unpopular policies.

"Clearly the results have been immeasurably more crushing and unkind than I could ever have feared," said Nick Clegg, the coalition's deputy prime minister and one of the few in his party to survive in parliament.

Looking utterly distraught, he quit as leader calling the results catastrophic.

Nigel Farage, leader of the anti-EU UK Independence Party, also stood down, keeping a promise he made should he fail to win a parliamentary seat. Although UKIP did better than ever before, winning almost 4 million votes, it only captured one seat.

"I haven't had a fortnight's holiday since October 1993," he told reporters in his typical cheery style. "I intend to take the summer off, enjoy myself a little bit, not do very much politics at all."

During a night of continuous shocks as results came in, the procession of well-known names to lose their seats had not been so great since 1997 when dozens of Conservative grandees were dispatched on a euphoric night for Labour under Tony Blair.

The most high profile casualty was Labour's Ed Balls, a former right-hand man of ex-prime minister Gordon Brown, who had been hoping to steer the economy as the next finance minister.

Instead, not only were his hopes of high office shattered, he lost his own seat.

TEARS

"Any personal disappointment I have at this result is as nothing compared to the sense of sorrow I have at the result that Labour have achieved across the UK tonight," said Balls, fighting back tears.

In Scotland, the SNP stunned Labour with a swing of almost 40 percent in one seat, while national election coordinator, Douglas Alexander, with hopes of becoming Miliband's foreign minister, was beaten by a 20-year-old student who became the country's youngest MP, and the party's Scottish leader Jim Murphy was also comfortably defeated.

"Tonight Scotland has lost so many great members of parliament from all across the country," said a gracious Murphy.

While the night was bad for Labour, it was an utter disaster for the Liberal Democrats.

They clung onto just eight of the 56 seats they had held, casting most of their senior figures into the wilderness in the party's worst performance since its predecessor Liberal Party won six seats in 1970.

Danny Alexander, who was number two at the Treasury, ex-energy secretary Ed Davey and former business minister Vince Cable, whose London seat had not even been considered to be at risk, were among those ousted.

"This has been a terrible night for our party all over," said a clearly devastated Cable.

Another LibDem to be beaten was Simon Hughes, a veteran MP and one of the most familiar faces in British politics who was first elected to his seat in southeast London in 1983, five years before the party was even formed.

Parliament also lost one of its most colourful and controversial lawmakers in the shape of George Galloway, an outspoken Scot who once lauded former Iraqi leader Saddam Hussein and who had declared Bradford, the northern English city he represented, an "Israel-free zone".

"The venal and the vile and the racists and the Zionists will all be celebrating," said Galloway, the only lawmaker for the Respect Party which he founded.

"The hyena can dance on the lion's grave but it can never be a lion and in any case I'm not in my grave. As a matter of fact I'm going off now to plan my next campaign." (Additional reporting by Costas Pitas, Sarah Young in Margate and Maytaal Angel in Leeds; Editing by Giles Elgood)