Born in Maida Vale, his mother was from an Irish Catholic family and his father was a Protestant trades union official.
Randle and Pottle later wrote that they got Blake out of the area, first to Dover, hidden in a camper van, and then to a checkpoint in East Germany.
Pottle and Randle defended themselves in court, arguing that, while they in no way condoned Blake's espionage activities for either side, they were right to help him because the 42-year sentence he received was inhuman and hypocritical.
His obituary in The Guardian provided additional insights into his anti-war activism: the co-founding in 1967 of the "Vietnam Information Group to help US deserters and draft dodgers reach Sweden" as well as his involvement in demonstrations against the "Greek colonels' coup" and "against the Soviet invasion of Czechoslovakia".
His printing business was primarily involved in producing "leaflets for the peace movement and non-government organisations".