I read about this in my paper this morning. It's a real blow to them, however, I did think that the thief, although was wrong to be stealing anyway, probably didn't realise who Gerry McCann was, as according to the report, the wallet was taken out of his back pocket, so the thief would have approached him from behind. Also, I did think it was somewhat naieve (sp?) of GM to be walking around London with his wallet in his back pocket, especially in a rail station, those places are rife for pickpockets.
I hope once the person responsible realises who's it is, given the photos, he will at least return it anonymously to a police station.