Ukip has seized its second seat at Westminster in as many months, defeating the Conservatives by 2,920 votes in the closely-fought Rochester and Strood byelection.
The insurgent party’s victory amounts to a humiliating defeat for David Cameron. The prime minister promised to throw everything at winning the contest, visiting the seat five times and ordering his MPs to make at least three trips each.
Mark Reckless, a former Tory MP whose defection to Ukip triggered the byelection received 16,867 votes, or 42.1% of the poll.
His Conservative opponent, Kelly Tolhurst, took 13,947 votes (34.8%). The Conservative vote fell by 14.4%.
Labour’s Naushabah Khan came third with 6,713 (16.8%, down 11.7%) and the Liberal Democrats just 349 (0.9%, down 15.4%).
The Lib Dems came behind the Greens, who polled 1,692 (4.2% up 2.7%).
In his victory speech, Reckless told Britons that Ukip would “give you back your country”.
He said his win proved Ukip could win nationwide and called for voters to put the party in a balance of power position in parliament.
“Whichever constituency, whatever your former party allegiance, think of what it would mean to have a bloc of Ukip MPs at Westminster large enough to hold the balance of power,” he said.
“If you believe that the world is bigger than Europe, if you believe in an independent Britain then come with us and we will give you back your country.”
He also gave a mention to European migrants, after he was accused last week by Labour of wanting to see them repatriated if Britain leaves the EU. “They’re now here as part of our country, and they will always be welcome,” he said.
Nigel Farage, the Ukip leader, described the win as “massive” because it was the party’s 271st target seat. “Looking forward to next year’s general election,” he added, “all bets are off, the whole thing’s up in the air.”
Ukip’s margin of victory was not as high as some polls had predicted but it is still likely to increase panic in the Conservative ranks about strategy and messaging just six months away from the election.
With the party continuing to lose swaths of support to Ukip, Cameron’s leadership may now come under pressure.
Labour said its vote was squeezed by the other two parties, while the Liberal Democrats candidate Geoff Juby lost his deposit.
The result is poor for the Conservatives but does not augur well either for Ed Miliband’s hopes of winning an outright majority and performing well in the south of England. Labour had held the north Kent seat for 13 years until Reckless won in 2010 following some boundary changes.
Polling day was also overshadowed for Labour by the fact that one of its senior MPs, Emily Thornberry, had to resign from the shadow cabinet over accusations her tweet of a Rochester house draped in St George’s flags showed snobbery against her party’s traditional working-class voters.
Thornberry’s departure was an entirely unexpected twist on a night that was set to be dominated by damage to Cameron’s reputation and the possibility of further defections from the Conservatives to Ukip.
Senior Conservative sources have also expressed hope that the seat can be won back in May after voters have had the chance to give the government a kicking.
Turnout was just 50.67%, or 40,113 votes – lower than would be typical in a general election – and pollsters suggested Reckless needed a 10 percentage-point majority to be confident about holding the seat in the general election next year.
However, Ukip said the result would give the momentum needed to gain even more seats than currently expected at the next election.
Diane James, a Ukip MEP, told the FT: “We could get 20 seats. That would be the icing on the cake.”
Rochester and Strood was regarded as much less natural Ukip territory than Clacton in Essex, where the first party’s first MP, Douglas Carswell, another Tory defector, won last month.
There are therefore serious worries at No 10 about the possibility of further defections in the case of a defeat, after Reckless said he was in talks with two of his former colleagues.
On the campaign trail, the Tory chief whip, Michael Gove, insisted he was “absolutely 100%” sure there would be no more defections, regardless of the result.
Cameron has taken a different tone in recent days when the prospect of defections has been raised. Asked about his message to would-be switchers, he urged MPs to stay with him on the basis that moving to Ukip would be counter-productive in light of his EU referendum promise.
Farage gave strong hints that he believed more MPs would join him. Asked before the count whether Adam Holloway, the Eurosceptic Tory MP for neighbouring Gravesham, would defect, the Ukip leader said: “Who’s to say?
“Depending on the result tonight, let’s see what happens. There may well be a number of MPs who look at their own positions and think: do you know what, maybe this is the right place to be.”
Asked about Gove’s confidence about keeping all his MPs, Farage added: “I like Michael very much but since he went from being an excellent education secretary, his role as [chief whip] is not looking to be terribly good, is it? He’s getting most things wrong, and he’s probably going to be wrong about this too.”
The byelection campaign was dominated by the issue of the NHS and local schools but there were bitter battles over the issue of immigration, with Reckless criticised for suggesting that some immigrants could be asked to leave the country in the event of the UK leaving the EU. He subsequently flatly denied that this would be the case and infuriated his Tory opponent by accusing her of distributing “BNP-light” campaign material.
With all the mainstream parties vulnerable to Ukip’s taunts about them being part of a “political elite”, Thornberry’s tweet touched a particular raw nerve with Labour as Miliband tries to stop the seepage of working-class Labour votes to Ukip.
Her tweet simply showed a terraced house draped in flags and a white van outside, without any negative comment about its owner. Several newspapers managed to track down the inhabitant of the house, 36-year-old Dan Ware, who said he was upset about his van’s numberplate being circulated on the internet.
The first edition of the Sun newspaper’s front page referred to “Snob Labour MP’s dig at White Van Man England flags”.
The MP for Islington South & Finsbury initially defended her decision to take the picture, saying her critics may have been showing “a somewhat prejudiced attitude towards Islington”. But within hours, she apologised for “any offence caused” by the tweet after party sources made clear Miliband was furious.
Simon Danczuk, Labour MP for Rochdale, suggested it was “derogatory and dismissive of the people”. He told the Mail Online it was “like the Labour party has been hijacked by the north London liberal elite and it’s comments like that which reinforce that view”.
Just after the polls closed in Rochester at 10pm, it emerged that Thornberry had resigned following a second conversation with Miliband. A Labour source said: “She thought the right thing to do was to resign. Ed agreed.”