A seven-mile scarf knitted by over 5,000 people from around Britain and beyond has been rolled out between the Atomic Weapons Establishment (AWE) sites at Aldermaston and Burghfield in Berkshire.
The knitters are calling on Parliament not to replace the Trident nuclear weapons system when the decision comes up in 2016.
The event is the latest demonstration against Trident at the AWE, the site of increasingly frequent protests as the general election approaches in May 2015.
The campaigners described the action as a major step in increased public protest over Trident.
The protest was one of two major peace demonstrations in Britain today (9 August), the other being a 20,000-strong march against the Israeli government's attack on Gaza.
The sections of the scarf, which have been displayed individually in towns around the UK, were linked together for the seven mile stretch at 1pm today. The date was chosen as the anniversary of the atomic bombing of Nagasaki in 1945.
Activists holding up the scarf along the seven miles route observed two minutes' silence for the victims of nuclear weapons.
The knitters include people from all parts of the UK, as well as Kenya, South Africa, France, Austria, parts of South America and elsewhere.
The Wool Against Weapons initiative is organised by Action AWE and the Campaign for Nuclear Disarmament (CND). It is the brainchild of Angie Zelter, of Knighton in Powys, and Jaine Rose, of Stroud in Gloucestershire.
"This is just the start of people's mobilisation", said Zelter after the scarf had been unfurled.
She explained, "People have to act because the government won't disarm without people in their thousands taking to the streets. Many who have been knitting this scarf are now preparing to join the month of action at AWE in March, weeks before a general election that could determine the future of Trident."
CND's Kate Hudson said that actions such as today's protest are becoming more frequent.
She added, "It is a disgrace that this government is prepared to squander over £100bn on a monstrous Cold War weapons system, while it slashes funding for health, education and other public services.
She pointed out that opinion polls consistently show a majority of the British public to be opposed to Trident renewal, and insisted that the protests are "representing the majority of the British public who reject this phenomenal and immoral waste of taxpayers' money".
Hudson insisted, "The British public is increasingly fed up with being told there's no money left while exorbitant sums are earmarked for nuclear weapons."