I have actually been in the office of the Speaker of the House of Commons!
When Selwyn Lloyd retired as the Speaker, he had a painting of a racehorse in his office which belonged to the Horserace Betting Levy Board (where I was a minion) and I was duly despatched by taxi to secure return of said painting. The office is one of those that sticks out over the Thames and I can remember all the security that we had to go through to reach it.
Well I once had Prince Charles drive over my foot, or to be accurate, his chauffeur. Got quite a shock when it stopped and his head popped out the back to ask if I was OK.