THE Prime Minister has told MPs she would be prepared to press the nuclear button.

During an, at times, heated Commons debate on replacing Trident, the SNP’s George Kerevan told Theresa May how it was time to cut to the chase.

“Is she personally prepared to authorise a nuclear strike that could kill 100,000 innocent men, women and children?” asked the MP for East Lothian.

“Yes,” declared the PM to a mixture of grunts of approval and gasps of disbelief.

“The whole point of a deterrent,” she explained, “is that our enemies need to know that we would be prepared to use it, unlike the suggestion that we could have a nuclear deterrent but not actually be willing to use it, which seemed to come from the Labour front bench.”

Opening the debate, Mrs May said Britain had approximately one per cent of the world's 17,000 nuclear weapons.

"For us to disarm unilaterally would not significantly change the calculations of other nuclear states nor those seeking to acquire such weapons.

"To disarm unilaterally would not make us safe nor would it make the use of nuclear weapons less likely.

"In fact, it'd have the opposite effect because it'd remove the deterrent that for 60 years has helped to stop others from using nuclear weapons against us."

The PM described Britain's nuclear deterrent as an “insurance policy we simply cannot do without”.

She added: "We cannot compromise on our national security, we cannot outsource the grave responsibility we shoulder for keeping our people safe, and we cannot abandon our ultimate safeguard out of misplaced idealism.

"That would be a reckless gamble; a gamble that would enfeeble our allies and embolden our enemies; a gamble with the safety and security of families in Britain that we must never be prepared to take."

But Jeremy Corbyn pointed out how the debate was not about the nuclear deterrent but Britain’s continued possession of weapons of mass destruction.

"We're discussing eight missiles, 40 warheads with each warhead believed to be eight times as powerful as the atomic bomb which killed 140,000 people in Hiroshima in 1945. We're talking about 40 warheads, each one with the capacity to kill more than one million people.

"What is the threat that we're facing that over a million people's deaths actually deters?" he asked.

The Labour leader added: "I make it clear today that I would not take a decision that kills millions of innocent people. I do not believe the threat of mass murder is a legitimate way to go about dealing with international relations."

Angus Robertson for the SNP said it was “obscene” that the priority of the UK Government, and, for that matter, too many people on the Labour benches, was that at a time of Tory austerity and economic uncertainty following the EU referendum, to “spend billions of pounds on outdated nuclear weapons that we do not want, do not need and could never use”.

He added: “With debt, deficit and borrowing levels forecast to get worse after Brexit and with more than £40 billion to be cut from public services by 2020, spending £167bn, £179bn or £205bn - whatever the number is that the Government are not prepared tell us - is an outrage.”