The 90-kilometer (52-mile) march on the Atomic Weapons Establishment in Aldermaston, Berkshire, west of London, was organised by the Campaign for Nuclear Disarmament (CND), one of Britain's oldest anti-war groups.

It alleges that the Aldermaston facility -- which the peace trekkers intend to surround upon their arrival Monday -- is expanding to develop new nuclear weapons to replace Britain's ageing Trident submarine-based missiles.

The march set off from Trafalgar Square in London where, according to police estimates, around 1,000 people gathered for a CND rally to warn of the dangers posed by nuclear weapons.

"Fifty-nine years ago Hiroshima and Nagasaki were destroyed by the most terrifying weapons ever devised, and tens of thousands were killed," said veteran politician Tony Benn, referring to the 1945 bombings of the two Japanese cities at the end of World War II.

"That was a warning to the human race that we ignore at our peril," he told the smaller-than-expected crowd.

CND vice president Bruce Kent said the group wanted to "wake up a sleeping population" to the dangers that nuclear weapons still pose, a decade after the demise of the Cold War.

He said a UN conference in New York in May to review the Non-Proliferation Treaty would be a critical event in international efforts to abolish nuclear weapons.

WAR.WIRE