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.