The UK Independence Party has called on Tories to defect by parking an armoured personnel carrier outside the Conservative Party's spring conference.
UKIP members used an APC to protest outside the Tory conference
UKIP said the stunt showed it was "parking its tank" on Conservative leader David Cameron's "lawn".
Speaking from the vehicle's turret, UKIP Euro MP Nigel Farage demanded an apology from Mr Cameron.
Earlier this week Mr Cameron called UKIP members "fruitcakes, loonies and closet racists, mostly."
Mr Farage said he was also angered by Tory chairman's Francis Maude saying some UKIP members had "unsavoury connections" with the right.
He told the BBC News website: "We wouldn't have been here if it hadn't have been for Mr Cameron's intemperate remarks and for [Conservative chairman] Francis Maude's outrageous remarks."
Mr Farage said he wanted Tories to "put pressure" on their leaders to apologise for the comments, saying "nine out of ten" of the Tories he had met agreed with him.
Asked if UKIP was declaring war on the Conservatives, he said: "It is a war between UKIP and entire political establishment.
"You can not put a cigarette paper between the three major parties, which means there is effectively no opposition party in Britain today."
Earlier, he told BBC Radio 4's Today programme Mr Cameron had let Tory voters down "like a cheap pair of braces" and "turned his back on" low taxation and the European question.
UKIP has withdrawn its threat to sue the Conservatives for defamation, but says it will fight every Tory marginal seat in the next election.
Activists arriving at the Conservative spring conference in Manchester were greeted by about 30 UKIP demonstrators handing out leaflets. Their banner read: "Cameron's Blue Labour: lies and libels".
Mr Farage told Today Mr Cameron had turned his back on talking about the European question.
"He is running away from issues such as, should Britain govern her own trade policy?" he said.
"And frankly we now have 'New Labour or blue Labour' and what we're saying is that UKIP are here, we've got a track record in European elections but we're now going to be campaigning on a full range of domestic issues, come and join us, come and help us."
Mr Cameron is set to give his first conference speech as Conservative party leader on Saturday.