The Ukip challenge, as the local and European elections and now our ComRes poll shows, needs to be taken seriously.
After covertly and sometimes overtly encouraging Ukip, Eurosceptic Conservatives have given their party a mountain to climb.
Nigel Farage hailed the "most extraordinary result in British politics for 100 years" as Ukip topped of the Euro polls in England and Wales.
Prime Minister David Cameron has described Tory MP Douglas Carswell's defection to UKIP as "deeply regrettable" and "self-defeating".
William Hague has said Douglas Carswell's decision to defect to Ukip is "totally counter-productive" because only the Conservatives can offer the public a choice on EU membership.
The Leader of the Commons said: "It's a totally counterproductive thing to do, of course, because the only chance of real change in Europe, the only chance of having a referendum where people can decide to say in the EU or leave the EU is having a Conservative government."
Backbench Tory MP Mark Pritchard agreed with Mr Hague, saying Mr Carswell had made an "error of judgment" that would end up helping Labour in the 2015 general election.
Defecting Conservative MP Douglas Carswell says he want to "shake up" the Westminster "clique" with his move to Ukip.
Carswell said the Conservatives' failure to take a stand against the European Union was at the heart of his decision.
ITV News Political Correspondent Libby Wiener reports:
Ed Miliband has tweeted that Douglas Carswell's defection show the Conservatives are "too divided to stand up for hard-working families".
Douglas Carswell’s defection is not just a blow to David Cameron. It shows the Tory Party too divided to stand up for hard-working families
A senior Tory in Douglas Carswell's Clacton constituency has said news of his defection to Ukip has come as a "bolt from the blue".
Mick Page, the leader of Tendring District Council, which covers Clacton said: "That's come as a shock - a bolt from the blue."
Speaking to the Press Association he added: "We always thought he was a Conservative very much against Europe but we thought he would work within the party to achieve his aims. As far as I'm aware the Conservative association had no warning of this."
Douglas Carswell has said he is leaving the Conservative Party because too much of the leadership "aren't serious about the change that Britain so desperately needs".
The Clacton MP says too many Conservatives "talk the talk" on key issues at elections but have not done enough to make change happen.
Tory MP Douglas Carswell revealed he had not told David Cameron he was defecting to Ukip.
Carswell "I've not yet spoken to the Prime Minister...if I'd phoned him up beforehand you'd have heard about it in another way"
The Prime Minister and Mr Carswell's relationship has not always been friendly, with Mr Cameron once telling the Clacton MP he needed to "get a sense of humour".
ITV News Political Correspondent Paul Brand is following updates from the special Ukip press conference at which Mr Carswell is speaking.
Carswell says he thinks members of his local party will come with him. But feels sad to be leaving them.
Clacton MP Douglas Carswell has said he will stand down as an MP and then stand for Ukip in the resulting by-election following his defection from the Tories.
He today announced that he would be leaving the Conservative Party, claiming the party's leadership are "not serious" about the change the UK needs.
If successful, Mr Carswell would become the eurosceptic party's only Westminster MP.
The Conservative MP for Clacton, Douglas Carswell, has used a press conference this morning to announce he is defecting to Ukip.
Mr Carswell, long a strong eurosceptic voice on the Tory back benches, made the announcement alongside Ukip leader Nigel Farage.
The Conservative MP for Clacton, Douglas Carswell, has defected to Ukip.