Anti-nuclear protesters from across the country will stage a demonstration at the headquarters of the UK's Atomic Weapons Establishment.
The Campaign for Nuclear Disarmament (CND) said it expected thousands of people to join the protest at Aldermaston in Berkshire.
The event is aimed at putting pressure on the Government to scrap the Trident nuclear programme.
CND chair, Dave Webb, said: "Just ask the public if they would rather see £100 billion go on nuclear weapons or public services. When we could be spending this on education, healthcare, housing, public transport and other essential services, this is a shocking waste of taxpayers' money."
CND general secretary Kate Hudson said opinion polls showed that ordinary people had turned against Trident, and wanted to see it scrapped rather than billions being spent on a replacement.
"More trade unions have affiliated to the CND, as working people understand that money spent on Trident is money taken away from jobs, education, housing and social services.
"We are heading towards a situation where only a few dinosaurs back Trident and its replacement."
Speakers at today's demonstration will include Green Party and Labour politicians as well as activists.
CND said it was protesting at Aldermaston because nuclear bombs were made there. Supporters are being encouraged to bring pots, pans and musical instruments amid plans to surround the site with the "sound of protest."