He played a critical role in the Anti-Apartheid Movement, as an influential Labour MP who made anti-apartheid campaigning his political priority, and as its chair from 1976. With Archbishop Trevor Huddleston, AAM Executive Secretary Mike Terry and Hon Secretary Abdul Minty, Bob Hughes was a key member of the team which turned the British AAM into a mass movement of solidarity with the Southern African liberation movements in the 1980s and led to the election of Nelson Mandela as President of South Africa in 1994.

The Freedom for Mandela concert at Wembley in 1988 was a particular highlight of the AAM campaign.  The Freedom Walk from Glasgow the London and the ongoing recognition of Mandela by Scottish leaders resulted in Mandela's visit to that City after he was freed from prison.