Streetwise I'm not, says a chastened Alan Bennett

Playwright describes for the first time what happened when he fell for a scam and had £1,500 stolen from him

The playwright Alan Bennett has written of mad kings and deranged women, of black markets and Cold War Spies, and has railed against politicians and media moguls. However, as he is the first to confess, he is not streetwise. Writing publicly for the first time about his encounter with two pickpockets who stole £1,500 he had just withdrawn from a bank, he said the experience left him "less ready to believe in the kindness of strangers".

He was conned out of the money in June in Camden Town, London, when two women approached him in a branch of Marks & Spencer to tell him he had ice cream spilt down the back of his coat. The playwright said he walked from the bank, where he had withdrawn money to pay his builders, and into M&S where the women – "Italian by the look and sound of them" – tried to help him clean off the spilt ice cream.

"I take off my coat and they very kindly help me to clean it up with tissues from one of their handbags and another man, English, I think, big and in his fifties, goes away and comes back with more tissues," he writes in the latest edition of The London Review of Books.

"The ice cream (coffee-flavoured) seems to have got everywhere and they keep finding fresh smears of it so that I take my jacket off too to clean it up. No more being found, I put my jacket on again, thanking the women profusely, though they brush off my gratuitude and abruptly disappear.

"I go back to the car, thinking how good it is that there are still people who, though total strangers, can be so selflessly helpful, and it's only when I'm about to get into the car that I remember the money, look in my inside pocket to find, of course, that the envelope has gone."

After reporting the loss to the police he learned that the pickpockets were most likely Romanian and that the con is common enough to have been given the name "Mustard Squirter". It was thought "the women or their male accomplice" saw him in the bank and followed him into the shop.

He recognises that they were "very good at their job" but said: "Quite hard to bear is that I have to go back to the bank to draw out another £1,500 or the builders will go unpaid." And he added: "The casualty, though, is trust, so that I am now less ready to believe in the kindness of strangers."

At the time he was reluctant to talk publicly about the encounter, saying only that it was "most upsetting" and that he would record it in his diaries. This he has now done in the diary he writes annually in the LRB.

Later that day, having given his details to the police, Bennett answered his doorbell to find a reporter, giving her name as Amy, on his doorstep. "I close the door in Amy's caring face, tell a photographer to bugger off and come in and reflect that though the theft is bad enough, more depressing is that someone in the police must immediately have got on to the Mail." He wonders how much an Alan Bennett tip-off was worth.

The crime was brought back to him in September when he came across an old lady behaving oddly. He offered to help and assisted her to a bench, whereupon the "woman" stood up straight and was revealed as a man, an actor trying to create a BBC3 programme.

He lamented that the reality made the "whole encounter more ordinary" but thinking back to how easily he fell victim to the pickpockets a few weeks previously he recognised that "had this been a similar scam it would have been just as easy to pick my pocket again as I'd helped the 'old lady' to the seat. This had never occurred to me. Streetwise I'm not."