Ask a grown-up: Why do houses cost so much money?
It's got a lot to do with planning law. A long time ago, if you wanted to build a house, you just bought a plot of land and built it, and it would cost just as much as the wood and bricks you'd built it with.
After the second world war, the government introduced planning restrictions. It said: "You can build only where we say and you can have only a little bit of land to do so." This meant that, if you got permission to build a house, someone else couldn't build there, which restricted the supply of houses, so the price went up.
It is that supply and demand that makes houses so expensive. It's also because we live on an island with too many people on it, so there aren't enough houses for everyone, making them cost more. But don't worry about that for now – you've got a while before you need to buy a house, and you never know what may happen. House prices can go up or down. Anyone who says otherwise is talking nonsense.
Double Your House for Half the Money starts on 6 August at 8pm on Channel 4
If you're 10 or under and have a question that needs answering, email ask.a.grownup@theguardian.com, and we'll ask an expert for you.