The Scotsman newspaper said that Spike Milligan joined the Young Communist League "due to his hatred of fascists, who were gaining support near his home."
He would have been just 16 years old at the time of the 1934 British Union of Fascists Olympia rally and 18 during Cable Street.
The age demographic is about right and his claim to be "at the back (in Cable St) throwing rocks" sounds accurate and not a typical "Spike-ism."
Living in Catford, a long way from West Kensington, he may also have gone to Olympia with others - three young anti-fascists from south London were charged with insulting words and behaviour.
Having only just returned to Britain as a previously privileged Anglo-Indian, Spike's first conclusion on Britain was that he was working class.
In 1947, bereft of local currency when in a jazz band touring Yugoslavia, Spike jokingly claimed to have joined the Yugoslavian League of Communists to get a meal.
That distracts from the fact that he may have been entertaining volunteer youth brigades building railways.
It is certainly the case that Spike was a main speaker at the 1973 Morning Star rally at Festival Hall and he was still publicly calling himself a socialist in 1978 - note, not simply Labour.
Spike was an official sponsor of the May 1981 People's March for Jobs. Broad though this was, much of the early organisation was handled by communists and Spike was one of the first celebrities to sign up.
A reasonable conclusion is that Spike did not travel far from his teenage political roots but was very discreet about it, being a congenital non-joiner and having launched his career at the BBC during the cold war.