I read Mike Mulligan and his Steam Shovel  nearly every night to my 4 sons when they were younger (probably an unnecessary qualifier). It was also my favorite children’s book as a kid.
So, many of the squares of the capital’s super-prime real estate, from Belgravia and Chelsea to Mayfair and Notting Hill, have been reconfigured house by house. Given that London’s strict planning rules restrict building upwards, digging downwards has been the solution for owners who want to expand their property’s square-footage.
This trend reflects the appraisal concept of highest and best use  for the equipment despite the inherent wastefulness. Does it make sense to leave the equipment in the basement? With all the concern in the US about below grade empty oil tanks  and the environment, I wonder how this practice is allowed, cost effectiveness aside.
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.
You really need to read the book .