Farage confident as polls close
Polls have closed in the Rochester and Strood by-election, with Ukip leader Nigel Farage confident of delivering a second bloody nose to David Cameron and the Conservatives.
As tellers in Kent began the long process of counting votes, Mark Reckless appeared poised to join fellow Tory defector Douglas Carswell in returning to the Commons under the Eurosceptic party's banner.
Defeat would be a particularly wounding blow for the Prime Minister, who has personally spearheaded a concerted fight for a seat his party had claimed just weeks ago it had a good chance of holding onto.
The fear among the Tory high command is that a second convincing by-election victory for Ukip could encourage other waverers in the ranks to jump ship and join them.
And Mr Farage, whose party's dramatic surge in popularity has undermined Mr Cameron's chances of returning to Downing Street in next year's general election, said victory would put the result of the 2015 poll "up in the air".
"I feel our vote is solid. I think we are going to win but I think it's maybe closer than people think," he said, before the polls closed.
"It's rather High Noon because the Prime Minister in a sense put his own credibility on the line by almost being the candidate for the Conservative Party for the first half of the campaign.
"He has thrown the kitchen sink at it, they have thrown everything at this campaign. But do you know what? So have we.
"This matters because this is our 271st target seat. If we win this, looking forward to next year's general election, all bets are off and the whole thing is up in the air."
In a campaign dominated by immigration, Mr Reckless is the strong favourite to regain the constituency in Kent.
The Conservatives have already seen the previously safe Tory seat of Clacton fall to Mr Reckless's fellow defector to Ukip, Douglas Carswell.
The hope among senior Tories would now appear to be that the margin of their defeat will be sufficiently narrow to deter other potential defectors.
They have taken encouragement from some polls which have suggested that former Conservative voters planning to support Ukip in the by-election will return to them in the general election in May.
Ukip was hit by an eve-of-poll row after other parties seized on comments by Mr Reckless during a televised hustings to argue he had come "dangerously close" to advocating a policy of repatriation for immigrants from elsewhere in the EU.
After Mr Reckless claimed his words had been "twisted" by his rivals, Mr Farage was forced to step in to insist that those who had come to Britain legally would be entitled to remain.
Speaking after casting his vote, Mr Reckless said: "Today is not a day for politicians but for the people of Rochester and Strood. I ask their permission. We will see what their answer is later today."
Labour, expected to come in a distant third, ran a low-key campaign and sought to play down the significance of the by-election for its general election prospects, pointing out it did not need to seat to secure a Commons majority.
But it found itself thrust embarrassingly into the spotlight as the polls closed with the resignation of a senior MP over what was criticised as a "snobbish" tweet of a house draped with England flags.
Islington South and Finsbury MP Emily Thornberry posted the picture of the modern terraced house with three red and white Cross of St George flags and a white van in the drive along with the message "Image from Rochester".
After a social media and political backlash, she apologised after being given a dressing-down by leader Ed Miliband and Labour later announced that she had resigned as shadow attorney general.
Mr Farage - who is hoping to gain his second elected MP in the Kent constituency - asked: "What is Labour's Emily Thornberry trying to imply about Rochester and Strood? I suspect she's let Miliband's mask slip."
Eurosceptic Tory backbencher Philip Davies denied that he was planning to follow Mr Carswell and Mr Reckless by defecting to Ukip.
The Shipley MP told BBC2's Newsnight: "I agree with Nigel Farage on nearly everything. I'm sure there's some things I disagree with him about. I can't think of any off-hand. It's probably fair to say I agree with him on more issues than I agree with David Cameron."
But asked if he was tempted to defect to Ukip, Mr Davies said: "Absolutely not, because I'm a Conservative. Any particular leader isn't the party itself, it just happens to be whoever is the leader.
"The only way we are going to leave the EU is if we have a referendum. The only way we are going to have a referendum is if we have a Conservative government."
Asked if Mr Reckless was wrong to change sides, Mr Davies said: "If I had been in his shoes, I wouldn't have done it. Obviously, because I haven't defected and I'm not going to defect."
He added: "I've no doubt Mark will win the by-election, and if he does I'll be the first to congratulate him ... and I'll continue to work with him to achieve our common goal of leaving the EU."
Right-wing Conservative MP Stewart Jackson said: " Any Tory MP who defects to Ukip on the basis of the result in Rochester and Strood - whatever it is - would frankly be completely insane."
Cabinet minister Iain Duncan Smith declined to accept defeat despite Tory sources suggesting they had no hope of winning, insisting he thought the Conservative vote was "holding up pretty well actually".
"We have fought it. We want to win it. We don't know what the result is going to be. We will wait and see what happens. I wouldn't count chickens before they have definitely hatched," he told Sky News.
He insisted the vote was "not about the general election", which would be a fight between the Conservatives and Labour, and accused Ms Thornberry of "sneering at the electorate of Rochester".
"It seems the Labour Party doesn't even respect the people they expect to vote for them now," he said.