In this week's New Statesman, Ed Smith writes about the absurdity of London's housing market.
He describes the houses in the city's most prosperous areas, like Belgravia and Chelsea. London's strict planning rules restrict building upwards, so digging downwards has been the solution for owners who want to expand their property's square-footage.
Some truly ridiculous things have happened as a result.
For example, there's Roman Abramovic's £150m home, which extends three stories underground.
According to the Daily Mail: "The development, over five storeys above ground and three basement levels, boasts a cinema/entertainment room, an indoor pool, steam room and sauna, as well as a children's study and entertainment room."
Anyway, such conversions take massive amounts of work. They require small diggers to bore through, say, the house's rear garden and sometimes plough straight through the house.
That's right. They just poured a whole load of sand and gravel on top of the diggers and left them there.
We don't know how many diggers there are. It could be up to 1,000, one property developer tells Smith.
The Evening Standard quotes Don O’Sullivan, a director of London developers Galliard, who says the claims make no commercial sense:
“With the basement space worth up to £8,000 per sq ft why would someone leave such valuable space filled with dumped equipment and fill in concrete? Much more valuable to extract and have as sellable space – oligarchs are rich but not stupid.”