For London's multi-millionaires not even tough planning rules which restrict buildings from expanding upwards can stop owners increasing their square-footage.
More and more of the capital's super-rich are expanding downwards instead, and digging out mega basements.
But there's a problem. The diggers go so deep below ground, it can be difficult to get them out again. So what happens?
This week's New Statesman has a rather surprising claim - that they are simply buried in the ground. Dozens of diggers are just left there, predominantly in Belgravia, Chelsea, Mayfair and Notting Hill. Writing in the New Statesman, Ed Smith says:
Simply bury the digger in its own hole.
Given the exceptional profits of London property development, why bother with the expense and hassle of retrieving a used digger – worth only £5,000 or £6,000 – from the back of a house that would soon be sold for several million? The time and money expended on rescuing a digger were better spent moving on to the next big deal.
The new method, now considered standard operating practice, is to cover the digger with “hardcore”, a mixture of sand and gravel. Then a layer of concrete is simply poured over the top.
Digger? What digger? The digger has literally dug its own grave – just as the boring machines that excavated the Channel Tunnel were abandoned beneath the passage they had just created.
So how many diggers might be down there? No one knows for sure. One developer estimated at least 1,000.
However, speaking to the Evening Standard, Kevin O’Connor, managing director of Cranbrook Basements, dismissed the claim.
The suggestion is utterly ludicrous. Under no circumstances would this ever happen in a professional environment.
The diggers used are tiny little machines and they can be lifted out with a block and tackle. There is always an exit strategy for the equipment.