Although too young to travel on the Aldermaston march, as a fifth former I was in Manchester for a non-violent civil disobedience (or 'sit-down') organized, if I remember correctly, by the Committee of 100.

Bertrand Russell did indeed resign in October 1960 as CND president in order to head, along with Rev. Michael Scott, the Committee of 100.

The culmination of the activities of the C100 came with demonstrations at Wethersfield Air Base, Manchester, York, Cardiff, Bristol and Ruislip, the headquarters of the USAF in Britain.
The authorities zeroed in on six members of the C100, charging them with offences against the Official Secrets Act.
They were tried at the Old Bailey the following February and received prison sentences
With its main organizers in jail, from then on, the movement wound down.