Prime Minister Gordon Brown is expected to indicate today that Britain could be prepared to scale back its independent nuclear deterrent in the long-term interest of achieving a "nuclear-free world.", according to dpa. In a speech to the United Nations General Assembly, Brown is expected to say that Britain could be ready to cut its sea-based Trident submarine system from a fleet of four to three. He would then make the proposals to the Security Council on Thursday. "If we are serious about the ambition of a nuclear-free world we will need statesmanship, not brinkmanship." The number of missiles carried by the submarines will remain unchanged. In London, government officials stressed that maintenance of an independent nuclear deterrent remained "non-negotiable." The opposition Liberal Democrats said Brown's proposals did "not go far enough." The move comes at a time when Britain is debating the fall-out of the economic crisis and the high level of public debt as a result of last year's huge bank bail-out scheme.