John Walsh: 'I gave him £20. He and his gormless son instantly said: "Please, more!"'

Tales of the City

I've been mugged so often, I feel I deserve one of those loyalty cards, like they give you at Tesco or Waterstone's for returning time and time again for more. Soon, the muggers will be offering me 10 per cent discounts. By mugging, I don't mean being actually whacked and robbed in the street; I mean those more subtle occasions on which your stupidity, sorry, your kind heart, is exploited by felons with tales of woe.

I remember the ditzy doorstep caller, three years ago, who said she'd been locked out of her house up the road at number 126 (she waved an airy hand) and needed £20 for the taxi to her Mum's where a spare key could be found, and of course she'd pay me back because we were practically Dulwich neighbours. So I gave her £20, and only when the door had slammed behind her did I remember her hand gesture and think, Hang on, surely number 126 is in the other direction ...

I remember the weeping black youth in Camberwell, who showed me a pay slip to establish his bona fides (actually the piece of paper could have been anything – a boiler guarantee, the instructions for making an Airfix helicopter, an application to join the Wu Tang Clan) before asking for money with which to take a taxi to Luton to see his soon-to-expire Papa. I gave him £20, and rumbled him when he asked for a further £20 to enjoy a taxi back to London.

So I should really have felt a sense of déjà vu at the weekend when, while gliding down a slip road off the M4, I saw a portly middle-aged chap signalling for help in front of two parked cars.

I stopped and got out and the man – small, evidently Turkish, highly excitable – went into his story. He was, he said, a car dealer from Germany, on vacation in London with his family (he indicated a gormless teen behind him), and he'd run out of petrol while racing to catch a plane at Heathrow. He knew there was a garage 500 yards ahead. Could I oblige him with some money? To support his story, he waved a business card that showed his German auto connections, and brandished a fistful of gold rings which I could keep as "security" until he returned with the money.

What, dear reader, would you have done? I know, with hindsight, that I should have wondered how a car dealer could be so dumb as to run out of petrol, I should have wondered why he needed to pay cash for it and wondered how a foreign visitor knew there was a petrol station up ahead. I should have been alerted by the bogus reassurance of identity in that business card. I should have smelt a rat over the business with the rings (who, except a poltroon in a Brothers Grimm folk tale, ever fell for that Take-my-gold-jewellery-until-I-return schtick?) and I should've ostentatiously noted down his licence plates.

I didn't, of course. I gave him £20 to buy petrol. (Why is it always £20?) He and his gormless son instantly said, in chorus, "Please, more than £20!" Why? They waved at their stricken transport: "We have two cars to get to airport!" they cried, gesturing at me as if I were a slow-on-the-uptake petrol pump attendant.

The father offered me his gold (yeah, right) rings again, silently raising the amount he wanted from me, but I'd had enough. It was the second car that did it. The chances of a hire car running out of petrol on the M4 are low enough. The chances of a second hire car doing likewise at exactly the same time are a million to one. I waved his jewellery away and said coldly: "That's all you're getting."

They got back in the first car, and both vehicles roared off without any trouble. The man hadn't said to me "thanks for the money", before leaving. He'd just looked a bit miffed that I'd turned down his offers of bogus collateral.

The encounter left me feeling angry that I'd been conned again – this time on the hard shoulder of a motorway slip-road, no less – but also intrigued by our exchange of lies and suspended disbelief. As on other such occasions, I'd wondered if I was being conned – but kept going anyway, as if the dialogue was a performance or a battle of wits, to be enjoyed until I found a hole in the man's story. Why had I done it? Was I so rich and cavalier that I didn't mind losing £20 to a wily Turkish beggar? Or just too absurdly socialised to be able to tell a stranger to go and stick his gold rings up his astrakhan collar?