The peace movement was split over whether demonstration should be abandoned for more radical acts of protest such as civil disobedience. This is a form of direct action in which the law is broken in order to force an issue into the political and public arenas.
Advocates of civil disobedience argue that small crimes, such as the disruption of roads and public spaces, are justified when they are against far greater crimes such as massive environmental damage or war.
Civil disobedience often involves a breach of normal or legal boundaries: public spaces are disrupted and secret places are infiltrated. It is therefore often treated as trespass by the authorities.
In 1960, the activist and philosopher Bertrand Russell resigned his presidency of the Campaign for Nuclear Disarmament in order to form the Committee of 100. This more militant resistance organisation advocated civil disobedience in favour of peaceful demonstration, believing the former to be a more effective method of protest against nuclear weapons and the Vietnam War.
The Committee believed that personal risk and responsibility were key elements of resistance. This meant that they approached direct action without concern for their own security or fear of arrest and imprisonment.
The sit-in is a type of civil disobedience which uses disruption to draw attention to the protest and the protesters' cause. Protesters occupy an area, sit down, and remain seated until their demands are met or until they are removed by force. This method of protest was first used by Mahatma Gandhi in the Indian Independence movement against British rule and was later adopted by Martin Luther King Jr in the American Civil Rights movement. A sit-in can be effective even when it is broken up because the authorities are seen to meet non-violence with violence.
At the first Committee of 100 sit-in in February 1961 4000 protesters sat down outside the Ministry of Defence in Whitehall; in September of the same year 1300 were arrested in Trafalgar Square and 350 at an American nuclear submarines base at Holy Loch in Scotland
Civil disobedience has also been used to find out and expose information concealed or suppressed by government. Spies for Peace was a group of Committee of 100 members who felt that sit-downs were not having sufficient impact on the government's weapons policies. They advocated infiltration, broke into military bases and sought out unknown and secret government information.
The group first exposed detailed government's policies for the country in event of nuclear war. In March 1963 Spies for Peace broke into a secret government headquarters, the Regional Seat of Government Number 6 (RSG-6), to photograph and copy as many documents as they could find. They then distributed 4000 leaflets, which explained what they had found, to the national press, politicians and peace movement activists. A few days after the leaflets had been posted protesters were demonstrating at the site of RSG-6 and the activities of the Spies for Peace made front page news.