Ukip appeared to be the victim of a coordinated political and media attack today, just days ahead of the local elections.
Leaked internal emails appeared to show disarray at the very top of the party while new details emerged of extremist views among party candidates.
The party hit back at the stories by accusing the Tories of an organised smear campaign.
In an open letter to party leader Nigel Farage, Tory donor Michael Ashcroft said the eurosceptic party was acting against its own interest by challenging the Conservatives.
"You would probably accept that the Conservatives would suffer most from a strong Ukip performance at the general election. Yet a Tory government is the only hope you have of getting the referendum that could make your dreams come true," he wrote.
Ashcroft goes on to brand Ukip "the most successful none-of-the-above party of the day, but a none-of-the-above party nonetheless".
He adds: "In that sense, without wishing to upset you, you have become the heir to Clegg."
The Ashcroft letter will pale in comparison to those Farage received from Stuart Wheeler, the party's treasurer, and Godfrey Bloom, a leading Ukip MEP, earlier this week.
The emails, which were leaked to the Observer, saw senior figures admit they were not coming up with any policies because the party could not hold together the disparate individuals it had attracted.
"My experience thus far is that as soon as more than two people get in a room progress completely stops," Bloom wrote last Thursday.
"Even where we have experts of our own, they disagree."
The MEP even suggested purchasing policies 'off the shelf' from right-wing think tanks.
"Our website will have no policies at all on there for ten years if we adopt a neo-Byzantine approach to formulating them," he added.
"This means some quite senior members are going to have to stable their hobby-horses."
Interestingly, Bloom also raises concerns about the increased professionalisation of the party as it attracted new members who are out-of-tune with the old guard.
"Having worked on the defence paper for over one year it would appear Ukip has more military and naval experts than we have soldiers. Most of them do not agree with each other. It is like herding cats," he said.
"We are also attracting new members who bring main party 'baggage'. Focus groups, quotas, even political correctness.
"We must be wary of listening to these siren voices. We did not get where we are today by following, but leading."
The party is fielding 1,217 candidates in Thursday's local elections. Downing Street doesn't expect the party to win many councillors, but it could easily perform strongly enough to prevent Tory victories.
The drip-drip of negative Ukip stories which have emerged during the week – mostly around the behaviour and political views of councillors and candidates – bear all the hallmarks of having originated from Conservative HQ.
"Ukip has been subject to a co-ordinated smear campaign," a party spokesperson said.
"We have evidence that Conservative Campaign Head Quarters has been scrutinising each and every one of our 1,732 candidates, monitoring every social media output over the last few years.
"Were we inclined to return the favour, we would find even more examples to use against them.
"We deem that using our candidates as cannon fodder to undermine a political campaign, anti politick, morally reprehensible and downright dirty.
"We are an open minded party who believes that ordinary hard working men and women who want to serve their communities should not be subject to a political lynch mob."
Transport secretary Patrick McLoughlin denied those accusations to the BBC this morning.
"I don't know anything about a smear campaign. All candidates are put under scrutiny," he said.
Speaking on Sky News, Ken Clarke risked angering Ukip supporters by saying many of them were "closet racists".
He added: "Fringe right parties to tend to collect waifs and strays.
"The trouble with Ukip is it's just a protest party. It's against foreigners, it's against immigrants, but it doesn't have any positive policies. It doesn't know what it's for."
Responding to the scrutiny of Ukip's candidates and policy, former Liberal Democrat leader Ming Campbell said simply: "Welcome to Test cricket."
Today there were even more negative stories about Ukip members.
One candidate was accused of liking racist groups the English Defence League on Facebook while another allegedly said regular physical exercise could prevent homosexuality.