STRASBOURG, France (Reuters) -- Britain's nuclear missiles might be negotiable "at some point" as part of U.S. President Barack Obama's drive for a world free of atomic weapons, Defense Secretary John Hutton has said on the sidelines of a NATO summit.
Britain's parliament gave the go-ahead in 2007 to government plans to replace the Trident submarine-based nuclear weapons system, due to go out of service in the 2020s, with a new system at a cost of up to 20 billion pounds ($29.32 billion).
But the financial crisis and recession, which has forced Prime Minister Gordon Brown's government to borrow on a huge scale, has reopened debate about whether Britain can afford the new weapon system.
A renewed drive for nuclear arms reductions since Obama took office has also raised speculation that the British arsenal could become a bargaining chip.
Hutton welcomed an agreement between Obama and Russian President Dmitry Medvedev this week to seek a deal to cut the nuclear arsenals their countries built up during the Cold War.
Obama said on April 3 that he would set out an agenda in talks with European Union leaders in Prague on April 5 "to seek the goal of a world without nuclear weapons."
Asked if Britain's Trident system was negotiable, Hutton told BBC radio: "That might be a possibility at some point in the future, but we are certainly not at that point today."
For the British weapon system to become negotiable, "there would have to be a very significant breakthrough in international nuclear weapons negotiations," Hutton said.
Hutton said Britain could afford the new submarine-based weapons system but added, "We've got a choice to make -- of course, all governments do."
Britain has cut its nuclear arsenal by half in the past 12 years and now has fewer than 160 warheads available. It has the smallest arsenal of the five legally recognized nuclear weapons states.
"The U.K. has taken a series of measures in the last 10 years to reduce the level of our own stockpiles, but we do believe fundamentally in the importance of a credible minimum deterrent," Hutton said.
"If there were to be the opportunity for much more significant nuclear reductions, then we would be prepared of course to enter into those discussions," he said.
Brown has said Britain could consider reducing its warheads further as part of a multilateral negotiation. Hutton did not make clear if he was talking about potential reductions in warheads or possibly scrapping the entire new system.
A British parliamentary committee said last month that the Ministry of Defense must make fundamental decisions about the design of the new submarines by September, meaning the government will soon have to make more of a financial commitment to the project.
Britain's ruling Labour Party espoused unilateral nuclear disarmament until the late 1980s and then Prime Minister Tony Blair had to overcome a big Labour rebellion to win parliamentary approval for the new nuclear system in 2007.