I'd made it all the way to London before realising my passport was still back in the Midlands. There are mistakes you can solve with money and mistakes you can't. Fortunately, this was the first kind, although my credit card probably wished otherwise. I'd just got off the train at Paddington. I got straight back on one heading in the opposite direction, collected my passport and started doing the maths. There was no chance I was getting back across London and out to Stansted