When my youngest announced one bedtime that he must have a cricket jumper by first period the next morning or else, it could have been tricky. Nothing we're not used to of course -­ the ingredients of a from­ scratch Thai prawn curry for food tech at 11pm was the most recent crisis ­but still, tricky... If my mum hadn't been round, that is. But fortunately she was and before he had even finished the sentence, whilst the "jump-" was still passing through his lips, she was squealing with triumph: leave it with her! She had just the thing! And in the space of ten minutes she zoomed out the front door and back again flourishing the ancient not-­quite­-whites of my brother. All quite sweet and rather boring until I point out that my brother was nearly 50 at the time. He hasn't worn that jumper since Harold Wilson was prime minister. And my mum had moved house twice since then.

My mother, you see, is a hoarder. Every scrap of evidence of our 20th century childhoods is still tucked somewhere around in her 21st century house. She wouldn't part with a thing. Not so much out of a sentimental attachment you understand: more because it might­ (a favourite phrase) ­ 'come in'.

She grew up in the war. Possessions mean something to that generation. They were hard to come by and easy to keep. Nothing should be chucked, ever, no matter how potentially unpleasant or dangerous. I wouldn't dare mention the ingredients of the Thai prawn curry, for example ­- who knows what's still in the fridge left over from the era of Edward Heath?

Her attachment to all this stuff has always been a family joke. Oh how I have mocked... Until recently. Because now my own children are starting to leave home,­ the third out of four is just doing her A levels and soon to make a run for it -­ and as the space opens up and the dust settles I look around and realise that,­ oh dear,­ I haven't thrown very much out either. Everything from baby clothes through Brio and S Club 7 posters and out to skateboards is still in its place and I seem unable to move it. The place is like a wrecked ship or a Pompeii villa ­- preserved at the moment when the survivors had to flee.

Why am I like this when I don't even have the excuse of having lived through rationing? Not because any of it will ever come in, that's for sure. My kids have grown up in a world of Primark and Amazon. They're never going to see the point of making do or mending, sad to say. No, the reason I keep it all is the sentimental, emotional one. Those childhoods of my children went by so very quickly that I think I keep all this stuff as a sort of aide memoir.

Occasionally a loose photo will bubble up from somewhere, be borne along on the tide and somehow come before my gaze and I gasp: I remember that. Or I will wander into a now empty bedroom, find a storybook or stocking filler and think: of course. That is who they once were.

I won't be able to get away with it for much longer. My husband is, in this respect a ruthless, heartless machine of a man i.e. he doesn't half like a skip. A massive clear out is almost upon us and, much as I dread it, I really must comply. Otherwise this won't be a house anymore but a museum. We will be living in the museum of our children's childhoods. And I will have turned into my mum.

Gill Hornby is the author of All Together Now, out now, £14.99.