McGahey was, however, elected National Vice-President of the NUM in 1972. He made similar progress in the Communist Party of Great Britain (CPGB), being elected to its Executive in 1971. He remained a member until the CPGB dissolved in 1991 and then joined its successor in Scotland, the Communist Party of Scotland. He was reportedly the subject of phone tapping by the UK security service MI5 whose transcribers found him difficult to understand because of his accent and the effects of alcohol consumption.