Some property in London is so valuable that it has become more economical to bury excavation equipment after it’s been used to dig new basements than to retrieve it:

The challenge of adding new subterranean floors to London houses has become a highly lucrative business. The heavy lifting – or, in this case, the heavy digging – is usually contracted out to basement-conversion specialists. These firms discovered that it was reasonably easy to get a small digger (occasionally two) into the rear garden of a house on an exclusive 19th-century square. Sometimes they simply knock a hole in the wall and drive the diggers straight through the house. In other cases, the windows are so large that a digger can squeeze through without dismantling the bricks and mortar.

The difficulty is in getting the digger out again. To construct a no-expense-spared new basement, the digger has to go so deep into the London earth that it is unable to drive out again. What could be done?

A new solution emerged: 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.

This sounds like a circa 2006 story which is kind of nerve wracking.