My daughter has managed to colonise the downstairs rooms, too. We had friends over on Saturday and I asked, in what I hoped was a light and encouraging tone, whether she might take all her stuff off the top of the microwave.
'I haven't got any stuff on top of the microwave,' she said, outraged.
Several bottles of nail varnish, some lip gloss, various rings, hair clips and a small fluffy owl later, she still wouldn't admit guilt.
My son has the frightening habit of putting vital pieces of paper (exam timetables, revision notes, a provisional driving licence application) on the kitchen table where they are quickly buried under newspapers and bills. He then asks me, in an accusing voice, what I've done with them.
'If it's important,' I say, 'take it up to your room.'
'But I just put it there for a second,' he says, implying my tidying has got completely out of control.
Sometimes, in desperation, I gather up all their stuff and dump it back in their rooms myself. But this backfires horribly.
Recently, my husband bought my son a book he needed. It arrived in the post, and my son opened it. When I got tired of looking at it sitting next to the kettle, I took it upstairs and put it on his bookshelf.
Last week I came back to a very grumpy atmosphere. 'He can't find it,' said my husband. 'He says he's got no idea where it is.'
I went up to my son's room where he was lying on the bed listening to music.
'Look,' I said, pulling out the book from the shelf. 'It's here. Where it should be.'
'Well, how was I to know?' said my son.
Sometimes I think I might move out to the shed in the back garden and leave them all to it.