Jeremy Corbyn has backed calls for Theresa May to resign as Prime Minister for presiding over cuts in police numbers as Home Secretary.
In the wake of three terror attacks in three months, the Labour leader attacked Mrs May over Government cuts which has left the police with 20,000 fewer officers than in 2010.
Mr Corbyn conceded that Thursday's General Election was "perhaps the best opportunity" to remove the PM from her post, but asked by ITV News if he backed calls for Mrs May to resign, he said: "Indeed I would, because there's been calls made by a lot of very responsible people on this who are very worried that she was at the Home Office for all this time, presided over these cuts in police numbers and is now saying that we have a problem - yes, we do have a problem, we should never have cut the police numbers."
Asked a second time if he wanted the PM to quit, Mr Corbyn said: "We've got an election on Thursday and that's perhaps the best opportunity to deal with it."
The Labour leader has visited Middlesbrough and County Durham today, and is due in Gateshead this evening.
Mr Corbyn was quizzed on security as election campaigning went back into full swing after a brief pause in the wake of Saturday night's London Bridge attack.
It was the second time campaigning has been suspended since the snap election was called, with a longer break following the Manchester Arena attack.
The Opposition leader was asked by ITV News' Rachel Younger if he held Mrs May "in any way" responsible and if cuts to the police contributed to the London Bridge atrocity.
Mr Corbyn replied: "The primary responsibility for this lies with those who did it, they killed people in cold blood in a disgusting and appalling way and there's no words other than total condemnation.
"On the issues of policing - the Government has been warned repeatedly about police cuts, and the Police Federation and many others (have said) how 20,000 have gone down over the past seven years.
"We've said we'd put 10,000 back immediately and also increase the number of security officers that are available, because clearly intelligence is a very important part of this.
"It's also very important to have a message of bringing communities together and that is something I always give very strongly at all of my events."
Mr Corbyn also denied he had ever opposed the police having a "shoot-to-kill" policy when dealing with terror attacks, pointing out that an internal BBC investigation of an interview in which he discussed the issue in 2015 had found the report to be inaccurate.
The Labour leader said: "I have not changed my mind on shoot-to-kill.
"The criticisms that were made of me were I think wrong and unfair and indeed the BBC Trust upheld an objection on this.
"As far as I am concerned the police act, as they did on Saturday, as they did in Manchester, in defence of innocent life.
"That is a reasonable and proportionate response, as happened in Westminster."
Mr Corbyn also hit back at Mrs May's claims that Labour were arguing for police cuts of 10% in 2015, pointing out that the Government only protected budgets, which is in itself disputed, after Opposition and public pressure.
"We forced through a retreat on police numbers and I think it's wrong that she should use this opportunity to exploit the situation," he said.
The Labour leader also suggested that Mrs May broke the election truce after the London Bridge attack.
"I was surprised that only an hour after they announced they were suspending campaigning that a political speech was made on the steps of Downing Street," he said.
"It was bad timing of it and I think we should have all respected the pause in campaigning, my party certainly did."
Mr Corbyn later told the BBC: "There's an election on Thursday, that's the chance, and there's a call by people being made in the emergency services who say the cuts in police numbers during her time at the Home Office are appalling and that has to be challenged, and it's been challenged."
Shadow Cabinet Office minister Jon Trickett told BBC Radio 4's World At One that Labour did not want to get into a party political dispute, but serious questions had to be asked.
"I think we're going to sort this out on Thursday with the General Election," said Mr Trickett.
"I think people will look at what's happened, the cuts which have taken place, and form a judgment."
He added: "You're not going to have a resignation between now and Thursday."