John was a huge fan of what was probably the greatest comedy show on radio: "The Goon Show". John, it seems, had most of the 224 shows on tape.
Spike Milligan was their leader, the show ran from 1950 thru' 1959 - the end came because Spike wanted to move on to other activities (book writting, play acting, etc.). The Beatles lasted roughly from 1960 (Hamburg days) thru' 1969. The group did not go on mainly because John wanted out to devote himself to other artistic activities (and to Youknowwho).
So here it is - the same pattern for two extremely successful acts from Britain. I think if one looks more closely, he/she will find out more similarities between them.

