Sixty-one per cent of viewers chose Mr Clegg as the winner after the 90-minute showdown, according to an immediate online poll conducted by Populus for The Times. That compared with 22 per cent for David Cameron, the Tory leader and just 17 per cent for Gordon Brown.

The Liberal Democrats have enjoyed a 14 per cent surge in support among viewers who watched last night’s general election debate. Labour and the Tories turned their guns on Nick Clegg today, hoping to bring the Liberal Democrat leader straight back to earth after his outsider’s victory in last night’s first televised campaign debate.

Lib Dem officials were hailing their leader’s performance at the Granada studios in Manchester as a potential “game-changer” in a close election which already appears to have given the party its best chance of government for a generation.

Because of the demographics of the television audience, when the poll results were weighted to include the entire electorate, the Liberal Democrats' share of the vote slipped back to 24 per cent.

These weighted results put the Conservatives on 35 per cent and Labour on 28 per cent, a seven-point lead.

If the results of the poll of those who saw the programme were replicated through the population as a whole at the May 6 general election campaign, the Liberal Democrats would win 159 seats.

The LibDems party would still be the third biggest party in Parliament, just behind Labour (165 seats) and Conservative (294 seats), according to website Electoralcalculus

Afterwards, an early Sky News poll showed viewers thought Mr Clegg was the victor. He got 37% of the vote compared to Mr Brown's 32%, with Mr Cameron trailing in third on 31%.

Sixty-one per cent of viewers chose Mr Clegg as the winner after the 90-minute showdown, according to an immediate online poll conducted by Populus for The Times. That compared with 22 per cent for David Cameron, the Tory leader and just 17 per cent for Gordon Brown.

On Economy Gordon Brown said last night he “feared for the economy” if the Tories came to power.

He said they would take “six thousand million pounds” out of the economy in nine months and Labour had been right on the “big choices”. He said the money cannot be withdrawn now, adding: “The Tories are a risk to the recovery”.

David Cameron attacked public sector waste, saying cutting it would be good for the economy.

But Nick Clegg said “mythical savings” are the “oldest trick in the book” and invited them to “come clean” on the size of the structural deficit.