I do think how we control the supply of land is a really important issue; I'm not convinced this is going to be a particularly productive way to do that, but I'm certainly open to evidence. There's a real public interest here—the greatest windfall, I should say to you, Minister, of course, is when land is zoned for building when it had a previous use, especially if the previous use was agricultural. And, you know, there is a real—. The biggest factor in high house prices is actually the price of land. So, there is a real public interest to have a more equitable system over some of these forces, which is why I quite like Oliver Letwin's more holistic examination of this particular area. But 7,600 homes could be built if all the current land plots were used and that's over a year's supply of housing at our current rate that we need to increase that.

I think a couple of Members—Neil Hamilton mentioned it directly—. We need a system, if we're going to go down this track, that is flexible enough to take account of market conditions because some people could get penalised in a downturn when they've got every intention, actually, of using the land productively, but, for whatever reason, cannot get all the capital together to undertake the building programme. And so I think (1) you could set the bar quite high; you could say that the tax only gets applied after 18 months or two years—you could do that, and that would give you time to assess market conditions—or, if you're going to do it after a year, have certain ways of being flexible, should market conditions require that. So, I think it is worth us looking at this, but, as I said, I'd like to reserve my position until we see further evidence. And, as you said, the model is used in some other countries, so I think a further examination of the situation there—particularly over how it does produce a more effective market, because I think that's really, really important. We could end up undermining the market at certain times if we're not careful.