Britain's new Conservative-Liberal Democrat government said the announcement, timed to coincide with a UN nuclear non-proliferation conference in New York, was intended to build trust between nuclear and non-nuclear weapons states and to contribute to worldwide nuclear arms reduction efforts.

Britain had until now disclosed only the number of operationally available nuclear warheads for its Trident missile-armed submarine fleet, and had given no figure for the overall stockpile.

"In the future our overall stockpile will not exceed 225 nuclear warheads," Foreign Secretary William Hague told parliament.

The ceiling on operationally available warheads would stay at 160, he said. The extra warheads allow for "processing, maintenance and logistic management," officials said.

Hague said the new government would review Britain's policy on when it would consider using nuclear weapons as part of a defence and security review launched by the new government, which took office after the May 6 election.

Reuters