Why don't new build houses in the UK have basements?

Seeing as land is so expensive, why don't builders dig down and add basements to new build houses in the uk. Is it becuase a) its too expensive, b) the only land left is poisonous landfill and/or floodplain, c) plain greed on the developers part?

Why don't new build houses in the UK have basements?
Generally, a basement is done during construction for 1 of 2 reasons. The primary reason is that a foundation must get solid non-moving ground to sit on or the house will heave, crack, tilt and generally move around and fall apart over the years. In areas where frost gets in the ground and the ground freezes; you must dig deeper than the frost. Older houses used to go the minimum. The standards evolved over the years to dig deeper and thus make the basement more usable space. It is very costly to dig, form and finish a sub-grade foundation and if the purchasers accept a slab or a 4 foot crawlspace, that will remain the standard in your market for a "stable footing". If you spoke to your builder prior to construction and your purchase, you might get them to dig you out a foundation as an optional extra to your house. It will cost more but thus the second reason for a basement if the environment doesn't need it: a luxury at a cost. Land is finite. A progressive builder/developer should look at all methods to maximize the use of the land at hand when planning a build. If a group of folks approached a builder for the same option; the price may reduce somewhat if the builder could accomodate you and also make a profit on the option.
Reply:the answer could be a] and b] new houses built near me recently went built on flood plain and have no basement.
Reply:In the US it is just cheaper to do it on a slab, so I guess it is the same there.
Reply:It would require a completely different and more expensive foundational structure. Its not so much the greed of developers thats to blame in as far as they would only pass the additional cost on to homebuyers - many of whom already struggle enough to get on the property ladder as it is.
Reply:probably greed and expense... a builder makes money the faster he can produce a house. the added selling value of a new house probably does not justify the extra time and cost to build a basement. If a builder can pump out a house with no basement in a month and sell it for xx, or the same builder needs a month and a half to build a house with a basement, and doesn't see a big enough profit from it, it is probably just not worth it for them
Reply:a and c