Boris Johnson has launched a fresh attack on David Cameron for "shamefully" spending £9.3 million of taxpayers' cash on a pro-EU leaflet.
London's mayor rounded on the "scare" tactics of the remain campaign as he continued his northern "Brexit blitz" tour.
But the start of his speech was interrupted by hecklers shouting "no Tories in Newcastle" and a group of women with at least one small child with them were escorted out.
Mr Johnson joked that when he cycles around London people know who he is and shout out things at him "like those kindly people" who disrupted the event.
He told the crowd that, unlike anonymous politicians and bureaucrats in Brussels, voters can hold him accountable.
"People know what I do, they shout at me in the street rather like those kindly people. They shout 'you Tory t****r or whatever.
"They know who I am, they know what I do. Who knows what's going on in Brussels?"
In a swipe at the Prime Minister, Mr Johnson said the remain supporters were "shamefully spending £9.3m of taxpayers' money on a leaflet trying to scare everybody into remaining in the EU".
"In the scare tactics of project fear they are woefully underestimating this country and its people and what we can do."
Senior Tories have warned that the campaign is pushing the party to the brink of "civil war" and it is facing "grave" consequences, whatever the outcome of the vote.
Mr Cameron "wouldn't last 30 seconds" if voters back Brexit in the EU referendum, according to one former Cabinet minister.
But potential successor Mr Johnson said "obviously David Cameron should remain in place".
Asked if he would be Prime Minister on June 24, Mr Johnson told the rally: "I certainly won't".
The mayor said he had told Mr Cameron he didn't understand why the premier had revealed he would step down before the next general election.
"I don't see the logic of that at all," he said. "I hope very much that he rescinds that position. There is no reason at all for that."
Mr Cameron earlier this week insisted he would remain Prime Minister even if he lost the June 23 referendum.
But Ken Clarke told Radio 4's Week In Westminster such a position would be "farcical".
"The Prime Minister wouldn't last 30 seconds if he lost the referendum and we'd be plunged into a Conservative leadership crisis which is never a very edifying sight," he said.
The veteran Tory said the mood in the party was heading towards the bitter divisions that left it badly damaged following clashes about the EU under Sir John Major.
Mr Clarke said: "It's dangerously close to it. And we've all got to make sure on both sides that it doesn't go back that way. The party was unelectable because it had just had the most appallingly bitter civil war and it was impossible to see how it could carry on. Now we mustn't repeat that, I agree."
Senior Tory Bernard Jenkin warned of "grave" consequences for the party, whatever the outcome of the vote.
He told the programme: "I think the Conservative Party will be in grave danger from the consequences of the result. I think a lot of people will leave the Conservative Party.
"I expect whatever emerges from the wreckage of Ukip will be more potent than before. I think these are very great dangers. And a Remain vote paradoxically makes a (Jeremy) Corbyn government somewhat more likely because the Conservative Party will be in such an unhappy state."