Tonight’s vote in the House of Commons was 472 for and 117 against, a government majority of 355.
Prime Minister Theresa May urged MPs to back renewing the nukes – and confirmed that she would be prepared to press the nuclear button.
Asked directly if she would be willing to “to authorise a nuclear strike that can kill a hundred thousand innocent men, women and children?” Mrs May said with steely determination: “Yes.”
She said: “The whole point of a deterrent is that our enemies need to know that we would be prepared to use it.”
The UK retaining its Vanguard nuclear subs “remains as necessary and essential today as it was when we first established it,” she added.
“The nuclear threat has not gone away, if anything it has increased.”
The Government’s motion had called on MPs to support the decision to replace the current fleet of Vanguard class subs with four new Successor class boats.
It estimated the cost at 31bn pound with a 10bn pound contingency fund – with the cost to be spread over 20 years.
The new programme would be operational until the 2060s.
The debate saw Labour MPs again turn on their leader Jeremy Corbyn – a lifelong opponent of nuclear weapons.
He was heckled when he said he was voting against renewal – against Labour Party policy – and was accused of helping “the country’s enemies”.
With their party divided, Labour MPs were given a free vote.
The head of the GMB trade union Tim Roache had warned that 45,000 jobs around the country – many of them highly skilled – depended on the programme going ahead.
Mrs May said it would be a reckless “act of gross irresponsibility” for Britain to lose “the ultimate insurance.”