Tourists are go

I walked from Victoria up to Oxford Circus this morning where I was meeting my brother. As I approached Buckingham Palace I started to brace myself for the anticipated throng of visitors, there to see those blokes in tall hairy hats. Then I heard a brass band strike up; four slow chords which I recognised but couldn't immediately place. 5 - 4 - 3 - 2 - 1, it was the Thunderbirds theme tune. I have checked on Google and it was first played prior to the cavalry charge at Waterloo.