Bustling Borough Market on the south side of London Bridge is one of London’s gems. Around the artisan food market have sprouted pubs, bars and restaurants. It is a very modern London creation, an international fusion of the new and the old in which proper old boozers sell proper beer alongside wine bars and an assortment of eateries, including possibly the capital’s best tapas restaurant.

On Saturday evening, three Islamist scumbags came to this joyful spot intent on murder. Seven people died and around 50 more were injured. Armed officers were on the scene rapidly and, astonishingly, within only eight minutes of the first incident they had shot and killed the three terrorists.

As seems to be standard now, political campaigning in the general election was the next morning suspended. This is a mistake, for two reasons.

First, it hands a form of victory to the terrorists who seek publicity and notoriety. Television schedules were cleared for non-stop coverage of the murders and only four days from polling day – in which the country chooses a government for the next five years – the focus is on the bad bastards who wanted attention for their campaign to disrupt and destroy our way of life.

Second, ‎a suspension of campaigning and debate reduces the amount of time available to discuss what has become perhaps the defining issue of an election that was supposed to be a Brexit election, before it turned into a public services election and then became, perhaps, a security election. We need urgently to talk about what more should be done to defeat the extremists.

It will no doubt be thought tasteless to mention any of this now. But if not now – during an election when extremists are killing youngsters and their parents attending a pop concert in Manchester and stabbing people who just went out for a drink in London – then when? What could be a more important subject for discussion? And what is a better criterion for measuring the two people who seek on Thursday to be Prime Minister than their respective records and views on security, terrorism, extremism and policing?

There are some difficult questions for the Prime Minister to answer. She was Home Secretary for six years before moving into Number 10. Are the complaints from the police about funding justified? What about the scrapping of control orders? In the years after 9/11 there was a major investment in MI5, MI6 and GCHQ. Was it enough? Today, Theresa May talked impressively of enough being enough and pledged to increase prison sentences and to root out extremism. Quite right, but why did it take this spate of attacks (three this year so far) to speed this commitment to stronger action?

While these questions are legitimate and important, what is not in any doubt, however, is that May is on the right side with the right instincts in a way that cuts across party. She is committed to tackling terrorism and to winning the battle with our enemies.

The same cannot be said of the instincts of Jeremy Corbyn, whose disgraceful career has seen him side time and again with Britain’s enemies. The Labour leader has been utterly shameless during this election campaign in misrepresenting his support for the IRA, for example. To listen to him, and members of the Corbynista cult, you would think that he was in the 1980s a cross between Gandhi and Martin Luther King.

Corbyn was (is?) a supporter of Irish Republicanism. In pursuit of that goal he did not fraternise in the 1980s with moderates such as the SDLP. He completely ignored them. Instead, he was a fanboy of Sinn Fein who even attended a memorial for IRA terrorists shot by the SAS. Read Corbyn’s statements carefully and you’ll see he lamented the deaths of civilians and IRA members, as opposed to the killing of British troops and ‎police officers.

On the question of dealing with terrorists robustly, he is simply not to be trusted. On that we should take him at his own word and study what happened when he came under pressure having won the leadership‎ in 2015.

When he was interviewed by the BBC late that year he famously said: “I’m not happy with the shoot-to-kill policy in general. I think that is quite dangerous and I think can often be counter-productive. I think you have to have security that prevents people firing off weapons where you can.”

It was a jaw-dropping moment. The implication was that rather than soldiers killing terrorist leaders in the field, or armed officers taking down terrorists during an attack, they should instead attempt to have a cup of tea and engage in a nice chat with the extremists about the menace of what Corbynistas regard as Britain’s colonialist, imperialist, fascist, capitalist foreign policy.

There then ensued the most tremendous row, and Corbyn came under sustained pressure from appalled Labour moderates. This was when Corbyn was new to the job and still speaking his mind in a free-form rolling monologue of beardie weardie far-left and anti-British nonsense of the kind he had specialised in for the preceding forty years.

After a slating at a meeting of the Parliamentary Labour Party, he “clarified” his view. He told Labour’s ruling NEC that “any kind of shoot-to-kill policy” posed “clear dangers to us all.” He added: “But of course I support the use of whatever proportionate and strictly necessary force is required to save life in response to attacks of the kind we saw in Paris.”

His handlers in the aftermath of that revealing incident became better at concocting misleading forms of words that gave him enough cover – just.

May has questions to answer today, of course. But the questions facing Corbyn are of a different order. On Friday morning he could be Prime Minister. With that in mind, remember the authentic voice of Corbyn, musing about shoot-to-kill: “I’m not happy with the shoot-to-kill policy in general.‎” At Borough Market it was brave police officers who shot to kill and saved a lot of lives.