It's not Sod's law so much as Crow's first principle: on the one day I absolutely have to get to the opposite side of London, the Underground's bolshy union boss decides to shut down the network.
As somebody from the provinces, where if you miss one bus you'll likely have grown grass before another one arrives, I've always been a huge fan of London's public transport system and its ability to whisk you around the capital in its grimy embrace.
But with the Blunderground knocked out of the equation - and a five-mile gap between Paddington station and my destination - I decided to drive instead. And the experience was far less traumatic than I was expecting.
Of course, traffic was terrible, with the A40 bearing more resemblance to a 1:1 diorama than a busy dual carriageway. But the jam seemed to bring out a softer, more considerate side to London's motorists that I've never seen before.
Maybe you could even call it latent Blitz spirit. People let each other in and out and chatted between cars when everything ground to a halt. I even saw a battered Transit stop next to an overcrowded bus stop to load up with hitchhikers.
And, once beyond the £8 barrier of the congestion charge, things seemed to be pretty much as normal, apart from the fact that every bus was packed to about 150 per cent of its maximum capacity. I actually arrived at my destination a good hour before I had expected to.
Now all I've got to do is get home again…