I THINK I might just have paid £2,600 for Senior Son to sleep in a dustbin. And it's all to do with the shape of his bum.

He is hopeless with plastic cards - bank cards, cheque cards, guarantee cards. In the three years since he's had his own cash card, he's probably had about half a dozen or more. Since Barclays were foolish enough to give him a credit card a year ago, he's notched up three of those. And he's on his third, or is it his fourth Yorkshire Bank card, which considering he only opened the account at Easter is pretty good going.

The problem is that he won't use a wallet. Instead, the cards live in the back pocket of his jeans. Not very sensible, I know, but there you go.

And there must be something very odd about the way he sits down, because every now and then he comes home and says plaintively "My cash card won't work any more" and holds up a pitiful looking card bent to the point of almost snapping in half.

I find that quite hard to do with my bare hands. How he manages to do it with his bum...

Before he went on his first foreign holiday alone, I thought I'd solve the problem by buying him a wallet. They couldn't snap in half in there, could they?

No. They got stolen instead. Wallet and all. Which is why last summer, barely 24 hours after I'd waved him goodbye, I had this forlorn phone call from Corfu, asking me to stop his cards.

Then, of course he loses them. Well, not so much loses them, but just puts them down somewhere in the chaos of his room. The chaos is like a living heaving monster. Anything put on its surface is immediately swallowed, not to be seen again, until months or years later a card will emerge tucked between an old copy of Mix Mag and a couple of smelly socks.

Anyway, two weeks ago, I installed him in his new home in Manchester. Unlike the Headingley slum where he lived last year, this is state of the art student accommodation - a new block, each room with its own en suite shower and loo, telephone point, security cameras everywhere, locks, double locks.

And entry is by swipe card. He won't last, I know he won't.

"What will you do when you lose your card?" I asked, pointing out that there's a £15 charge for a new one. "What if it's in the early hours of the morning? Where will you go?"

We were walking past the dustbin shelter at the time. "I'll sleep in there," he said.

He'd only been gone a week when he rang me late one night (the night I'd gone to bed early of course). Could I cancel his Barclay cash card? And his Yorkshire bank card? And his Visa Card?

He'd lost them in the city centre after going to watch Darlington at Macclesfield. I groaned my way to his room, found the bits of paper. The phone rang again. "It's alright mum" he said cheerily, "I found all my cards on the floor of the taxi."

This time he's safe.

Next time, it's bound to be the bins..