UKIP is on the verge of holding the balance of power after the next election, its leader Nigel Farage claimed after his party won its first elected seat in parliament.
The party caused a political earthquake by beating the Tories to one seat and narrowly failing to pick up a second from Labour.
In a blow to Prime Minister David Cameron’s leadership, former Tory MP Douglas Carswell comfortably won back his Clacton seat in Essex with 60 per cent of the vote, having stood down to fight it again when he defected to Ukip.
However, in the shock of the night, Ukip came within 617 votes of taking the Heywood and Middleton seat in the north-west of the England, putting Labour leader Ed Miliband’s position under the spotlight.
The results built on the anti-EU party’s momentum from the European Parliament elections earlier this year, when it topped the national poll with 28 per cent, and a triumphant Mr Carswell described it as “an end to the cosy cartel politics” of the old established Westminster parties.
Reflecting on another strong night for his party, Ukip leader Mr Farage proclaimed that his party will win the seat of Rochester and Strood in Kent in the forthcoming by-election where another defector from the Tories, Mark Reckless, is standing for re-election.
He boasted that his party now has a realistic chance of holding the balance of power after the election in May next year.
“The whole of British politics has been shaken up in a way that the complacent Westminster class could never even have contemplated,” Mr Farage said.
“Something big is happening here. People want change. They have had enough of career politicians in three parties who don’t even understand the problems they face in their everyday lives. People want real change.
“We’ve got a chance here in a general election next year that is likely to be very tight, in an election in which no one party is likely to have a majority. If Ukip can keep this momentum going, we could find ourselves next May in a position where we hold the balance of power.”
Meanwhile, a beleaguered Mr Cameron, visiting a school in his Witney constituency in Oxfordshire, said the rise in support for Ukip could open the door to a Labour government.
“This speaks to a wider truth that if you vote Ukip, you are in danger of getting a Labour government with Ed Miliband as prime minister, Ed Balls as chancellor,” he said.
“You’ll get no action on immigration, no European referendum and, most importantly, you won’t get a continuation of the plan that’s delivering success for our economy and security for our people.
“That is the wider lesson of last night. We have seven months to demonstrate that only a Conservative government can give people the stability and security we all want to see.”
The results were potentially even more damaging for Labour, which had been expected to hold on to Heywood and Middleton relatively comfortably.
Speaking on the steps of Heywood library with winning Labour candidate Liz McInnes, Mr Miliband said the result showed the “scale of disillusionment” among voters.
He said Labour needed to demonstrate it could “listen and deliver” on jobs, housing and wages, as well as addressing “specific concerns” about immigration – a key Ukip theme on the doorstep.
“These results show the fight that we face over the coming seven months” he said. “This is a fight against disillusionment and despair, this is a fight for the working people of Britain and this is a fight that I am determined to win.”
However, with Ms McInnes only winning the seat on a 36 per cent turnout with 11,633 after a full recount, the result put more pressure on Mr Miliband’s leadership of the party with briefings that former home secretary Alan Johnson is being urged to challenge him. She said: “We hadn’t anticipated the way the Tory vote would collapse so much.
“I am going to work damn hard in this constituency to make sure people know they have an MP who will represent their interests.”
Senior Labour backbencher John Mann tweeted: “Ed Miliband does a lot of listening. Now he needs to do a bit more hearing.”
He also tweeted: “If Ed Miliband does not broaden the Labour coalition to better include working-class opinion then we cannot win a majority government.”
Meanwhile, veteran Labour MP Frank Field, who is in a group pushing for the party to sign up to a referendum on EU membership, said: “If last night’s vote heralds the start of Ukip’s serious assault into Labour’s neglected core vote, all bets are off for safer, let alone marginal seats at the next election.”
Ukip’s John Bickley came second in Heywood and Middleton with 11,016 votes, achieving an 18 per cent swing from Labour, while the Tory vote collapsed to 3,496 for Iain Gartside. The Lib Dem candidate Anthony Smith just held on to his deposit with 1,457, and the Greens’ Abi Jackson received 890.
Mr Bickley said: “Labour are in big trouble. This should have been a safe seat.”
Mr Carswell added: “The reality is that people want change and that is why they are turning to Ukip. It is the only party offering change.”
He suggested that the Heywood and Middleton result “shows that the Conservatives are splitting the Ukip vote. So a vote for the Conservatives is a vote for Ed Miliband”.
Mr Carswell won with 21,113 votes ahead of Tory Giles Watling with 8,709, and Labour’s Tim Young with 3,957.
Meanwhile, the Lib Dems won just 1 per cent of the vote and came fifth behind the Greens in their worst by-election ever.
Lib Dem Deputy Leader of the House Tom Brake said: “We are now a party of government and parties of government always do badly in by-elections.”
SNP Westminster leader Angus Robertson MP said: “These by-election results guarantee that Ukip’s Euro-hostile agenda will dominate at Westminster as the general election approaches.”