Theresa May has declared without hesitation that she would order a nuclear strike to kill hundreds of thousands of people if she thought it was necessary.
The Prime Minister gave the blunt reply during a parliamentary debate on the renewal of the Trident nuclear weapons programme, which many suspect was staged by the government for the sole purpose of drawing attention to the rift between Jeremy Corbyn and a majority of Labour MPs.
Ms May was challenged by the SNP’s George Kerevan, who asked: "Are you prepared to authorise a nuclear strike that could kill hundreds of thousands of men, women and children?”
She also told MPs that it would be "an act of gross irresponsibility" for the UK to scrap its nuclear weapons and accused opponents of the UK’s Trident missile system of being "the first to defend the country's enemies".
Previous prime ministers have avoided answering the hypothetical question of whether they would ever press the nuclear button. Sir Geoffrey Howe, who was Foreign Secretary in the closing years of the cold war, said it was a question no prime minister should ever answer directly.
But Ms May knew that the Labour leader was prepared to state his position, which is the opposite of hers. Without being asked, Jeremy Corbyn volunteered the statement that “I’m not making the decision that kills millions of innocent people.”
He added: “I do not believe the threat of mass murder is a legitimate way to go about international relations.”
The decision to stage Monday's vote was made by David Cameron, who sat three rows back saying nothing while his successor addressed the Commons.
Officially, Parliament was being asked to agree to spend up to around £30 billion renewing the four Trident submarines that are equipped with nuclear missiles and warheads. Every hour of the day or night, there is always one submarine patrolling the sea.
Trident was originally bought from the USA by Margaret Thatcher as a last ditch defence in case the armies of the former Warsaw Pact, which was disbanded in 1989, overran Europe.
Since 1989, it has been the official policy of the Labour Party to support the retention of Trident, to which Jeremy Corbyn, as a back bench MP, was consistently opposed.
He announced that he would vote against Trident again, but as he spoke, he was constantly interrupted by Labour MPs who demanded that he should defend the party’s policy instead of giving his own opinion. His response was that there is a review of Labour defence policy being carried out by the newly appointed Shadow Defence Secretary, Clive Lewis.