London: British MPs have backed the renewal of the UK's Trident nuclear weapons system, a move backed by newly appointed Prime Minister Theresa May. The MPs voted late Monday night 472 to 117 in favour in the House of Commons, the BBC reported. The vote approves the manufacture of four replacement submarines at a current estimated cost of 31 billion pounds ($41 billion). Defence Secretary Michael Fallon told MPs nuclear threats were growing around the world and Trident "puts doubts in the minds of our adversaries". Opposition Labour Party was split over the issue with 140 of its 230 MPs defying leader Jeremy Corbyn and backing the motion, the BBC added. A total of 47 Labour MPs voted against renewal, while others abstained. Although Labour MPs were given a free vote, many used the occasion to attack Corbyn, who is a longstanding opponent of nuclear weapons. The Trident fleet is based at HMNB Clyde, in Faslane, but all Scottish MPs taking part in the vote except for Scottish Secretary David Mundell, were against the renewal. The Scottish National Party opposed the move, saying nuclear weapons were "immoral" and the continued stationing of submarines on the Clyde could accelerate moves towards independence. The vote, by a majority of 355, came at the end of a five-hour debate, in which Theresa May spoke at the despatch box for the first time as Prime Minister. She said it would be an "act of gross irresponsibility" for the UK to abandon the continuous-at-sea weapons system, the BBC noted. Although preparatory work on renewal is already under way, Monday's vote gave the final green light to a new fleet of submarines which are due to come into service by the early 2030s. Concluding the session, Defence Minister Fallon said Trident had helped protect the UK for more than 50 years and to disown it now would be to "gamble the long-term security of our citizens". "Nuclear weapons are here, they are not going to disappear. It is the role of government to make sure we can defend ourselves against them," the BBC quoted him as saying. Since 1969, according to government documents, a British submarine carrying nuclear weapons has always been on patrol, gliding silently beneath the waves, somewhere in the world's oceans. The logic is to deter a nuclear attack on the UK because, even if the nation's conventional defence capabilities were destroyed, the silent submarine would still be able to launch a catastrophic retaliatory strike on the aggressor, a concept known as mutually assured destruction.