There is nothing inherently evil about nuclear weapons and they can play a positive role in preventing conflict, the defence secretary has argued.
In a keynote speech to King's College London today, Des Browne warned that although they have the power to do "great harm", he was not prepared to give up Britain's weapons as a deterrent against people who would hold the world "to ransom".
"In most circumstances imaginable, to use that power would be an evil thing to do. The question is, given that this power exists, is it wrong for us to have it, to deter others from using it against us?" he asked.
The government's white paper on Trident, Britain's existing nuclear weapons system, were published in December. It set out proposals to replace the system with a new set of submarines carrying up to 160 nuclear warheads, down from the current level of 200.
Although the three main parties are in favour of keeping some form of nuclear deterrent, many Labour backbenchers are against it, and the Liberal Democrats believe the government should delay a decision for several years.
Yesterday former White House advisor Richard Garwin told the defence select committee that the government's plans to replace the weapons system were "highly premature", and argued it could afford to wait until at least 2030.
However, today Mr Browne warned it could take 17 years to develop and test a new system, and although the lifespan of the existing warheads could be extended five years beyond their end date of 2017, said any further extension would be "risky" and costly.
He rejected the argument that nuclear deterrents were no longer necessary in a world where terrorists were the main threat to national security, saying it would be "irresponsible" to say a situation similar to the Cold War would not reemerge.
Despite international efforts, there was "no realistic prospect of a world without nuclear weapons in the foreseeable future", Mr Browne said, adding that no such weapons had been used in 50 years because, in part, countries like Britain had a deterrent.
The minister stressed the UK would continue to work towards cutting nuclear proliferation, but said the government's plans to renew Trident were not hypocritical and were fully compliant with the nuclear non-proliferation treaty.
Another key concern about replacing Trident is the cost, put by Mr Browne today at about 0.2 per cent of Britain's national income over the life of the new weapons system.
But he dismissed these fears, saying: "We believe that insuring ourselves and future generations against this devastating potential threat is worth this level of investment."
MPs will have a chance to debate the government's plans to replace Trident in March but with the support of the Conservatives, it is unlikely they will be defeated.
However, Lib Dem defence spokesman Nick Harvey reacted to today's speech by demanding a further cut in Britain's nuclear stockpile and new negotiations on full nuclear disarmament.
"Instead Tony Blair is determined to jump the gun and pour billions into a new nuclear system years before Britain needs to make a decision," he said.
To read our issue of the day on this subject visit Trident white paper.