The sight of all those youthful-looking police on the streets is, of course, guaranteed to make anyone feel old.
There are other signs of ageing. Catching the last train back to my hotel in Cardiff some time ago, it suddenly dawned on me that almost every other passenger was just going out for the evening rather than rushing home to fall asleep in front of Match of the Day.
Here's another sign you're getting on a bit: a footnote to a footnote to an historical figure.
According to the Margaret Thatcher Foundation, and who I am to disagree, I spent June 4, 1990 (when some of today's MPs were in school) interviewing the then Prime Minister.
It was a slightly surreal occasion, an hour one-to-one with one of the political giants of the 20th Century for a rather nervous, spotty hack.
She was slightly scary, although she did sort of apologise afterwards for a handbagging generated by some questions that gently suggested not everything in the garden was rosy.
The "Importance: Major" ranking has been added by officials. The best line from the interview was that she did not plan an early election (1991) but was thinking beyond that.
She was, of course, out of a job within five months of our interview, although that is probably a coincidence.
She may have been an ultra-divisive Prime Minister, but you have to admit she appears to have been very conscientious with the filing.