Like so many things in life, it was obvious with hindsight. But I had not lost a wallet to a pickpocket since 1986, when I was trying to get into Ferdinand Marcos's newly-liberated palace in Manila. Alas, I never did get in to inspect his wife's collection of 600 pairs of shoes, which became legendary the moment its discovery was relayed to the media.
In the press of the vast crowd, which had gathered the morning after Ferdy and Imelda's flight, I felt the wallet go. But this time, I felt nothing. It was a hot August morning in Barcelona, and Pat and I were walking down the hill from the Parc Güell, one of the spectacular memorials that form part of Antoni Gaudi's legacy to his native city.
That was mistake number one. Pat was feeling unwell, but I was greatly impressed by the modern and efficient metro system. We should have taken a cab to our next stop. Instead, we were walking slowly towards the train, slowly enough to look more than usually decrepit. So we must have looked an easy mark to the young man in American casual clothes - shorts, trainers, T-shirt and baseball cap, who (so Pat decided later) had been following us.
We should have known it was not to be our lucky day - walking down the busy high street towards the station, we were suddenly splattered with bird shit. It certainly felt like bird shit: there was rather a lot of it and the texture was slightly too pink. What else could it be? Step forward a helpful young man, who said in good-enough English: "How terrible. Can I help you clean up? Look at the mess, it must have been elephants."
I know, I know. Corny or what? But in that situation one is mainly concerned to get clean - that was mistake number two. There was a fountain across the street, our Good Samaritan explained. My initial reaction (it always is) was to reject help. But it was hot and he was decisive - mistake number three.
Actually, it wasn't a fountain. We stepped into the courtyard of a block of flats. "I live here," he said. "I have water and some paper tissues." All this happened in barely a minute. There seemed to be a lot of bird shit on my back (it must have been a low-flying bird). Anyway, my friend said: "Take your shirt off." Odd that, but I did.
He brushed me down, then said "Good luck, I'm late, I must go," and disappeared with a wave.
It was another two minutes before I realised I was travelling light. Keys in my right pocket (on the same bottle opener I bought at the age of 16), wallet in the left, I can barely move 10ft without being able to feel them there. Everything fell into place at that point. Just as I had realised too late in the Manila crowd that the man who accused someone behind me of taking the wallet was actually the pickpocket's accomplice, so I now realised I was the victim of a polished routine.
Pat had been wearing her handbag across her chest. That was why he'd settled for me, a few credit cards he wouldn't be able to use and the £100 in sterling, francs and pesetas which were (I think) inside the wallet. We phoned Marks and Spencer, whose Card Safe system we subscribed to in a moment of efficiency: they duly cancelled the cards.
For form's sake rather than insurance (what insurance?), we then reported to the local police station. Surprise, surprise, they knew this dodge rather well. Everyone we told laughed at us. "Hey, this is Barcelona," they said. Or " Beaucoup de vol a Barcelone ", as they put it across the frontier. After all, our hitch-hiking son had lost his rucksack, barely a foot away at the time, while on the phone at Barcelona.
Other friends had had bags razor-bladed and lost everything: car keys, car park ticket (nothing M&S can do about that), cards, everything except the mobile that allowed them to cancel the lot. Someone else's boyfriend, a lorry driver, had woken up in his cab to realise he'd been gassed and robbed. That was winter; in summer they concentrate on caravaners, she explained.
Oh yes, and there was the couple flagging down cars on the motorway, quite possibly one of whom was my mate in the baseball cap and T-shirt, because their caravan was "on fire". While kind-hearted friends of ours checked for the source of the smoke (a burning rag works quite well), chummy rifled the front seats of their opened car doors and made off. He probably said: "Good luck, I'm late, I must go."
Still, on my first visit since I hitch-hiked to Barcelona circa 1968, I liked the re-branded city and will go back. Probably with my wallet on a steel hawser.