CND has responded to reports from a public inquiry examining the state-led infiltration of political groups. The inquiry has identified a police spy who infiltrated CND between 1980 and 1984.

Kate Hudson, CND general secretary, said:

“If John Kerry was trying to disturb CND’s campaigning activities, it had no noticeable effect. No-one we’ve spoken to who was active at the time can even recall his name.

“There is a long history of state surveillance and activity to curb the impact of CND and other mass movements. While of course we’re opposed to such activities – it’s profoundly undemocratic – we have learned how to deal with it.

“Where we suspected undercover officers or agents at the time, we knew they were wasting their time because we didn’t have anything to hide – we just carried on regardless.

“Harry Newton, an MI5 agent who came to public attention after Cathy Massiter blew the whistle when she left the Service, is remembered as the person who stuffed envelopes as a volunteer. There are many similar stories.

“We have been fortunate that – as far as we know – no harm has been caused by these attempted interventions within CND. But we know that much distress has been caused in other movements and these activities absolutely have to stop.”