Updated: Oct 13, 2021
The fourth episode of series three, ‘The Saga of HMS Aldgate’, was broadcast 2 December 1952. The Radio Times listing is here.
There was an actual HMS Aldgate. I can find very little about it, except that it was launched on 5 April 1934. It was a ‘boom vessel’ or ‘gate vessel’, which – as far as I can make out – was a small-ish kind of boat specifically designed for laying nets to catch submarines. Which in itself sounds like something straight out of Spike Milligan’s head.
According to several online sources cataloguing naval vessels or Second World War events, HMS Aldgate was scuttled (i.e. sunk) in Hong Kong’s harbour on 19 December 1941 to stop it being captured by invading Japanese forces.
Not much of a saga, after all.