As Communist Party candidate for the Barnes Division of Surrey County Council, he polled 216 votes in the 1955 local government elections. As well as being a Vice-Chairman of CND (1981-84), he was a Sponsor of the British arm of the leading Soviet front body, the World Peace Council (WPC). He was Chairman of the J.D. Bernal Peace Library, founded by the former WPC Chairman and lifelong Stalinist Bernal in 1967. This was the group which published Mike's 1980 booklet Towards the Final Abyss referred to by Tam Dalyell.
When he set up "Scientists Against Nuclear Arms" (Sana) in 1981, Mike chose the Morning Star as the vehicle for an article explaining "how scientists can arm the peace movement with the facts". In May 1984, he went to Moscow at the invitation of the official Soviet Peace Committee to establish links with the Kremlin's "Scientific Research Council on Problems of Peace and Disarmament". Finally, he was listed as one of four activists due to represent another Soviet front, the World Federation of Scientific Workers, at the 1982 UN Second Special Session on Disarmament.
Mike Pentz never sought to conceal such controversial affiliations during his lifetime: it is misleading of the Independent to do so now that he has died.