Prime London’s mega-basements have been controversial in recent years, as owners look to add luxury subterranean spaces to homes that are otherwise limited for expansion options.

However, the research by Jefferies London has shown that whilst they may require months of substantial construction work they certainly add value.

Across London as a whole, the estimated asking price of a home with a basement comes in at £1.2m in the current market, some 97% higher than the wider asking price of a property.

However, this premium climbs as high as 122% across Westminster, where the average asking price of a home with a basement comes in at a whopping £2.762m versus a wider average asking price of £1.247m.

In Kensington and Chelsea, properties with a basement boast an asking price premium of 100%, whilst in Camden this premium sits at 98%.

For those buyers with pockets deep enough, the challenge in the current market is finding such a property – with this scarcity of stock no doubt contributing to the high premiums commanded by homes with a basement.

Hammersmith and Fulham boasts the highest level of prime basement property stock, but even then, these homes account for just 5% of all homes listed for sale across the borough.

In Kensington and Chelsea, prime basement for sale stock accounts for just 3% of all homes on the market, as is also the case in Camden.

The City of London boasts the lowest level of prime homes with a basement at just 1% of all listings.

A Jeffries spokesperson says: “Whilst their construction may have caused controversy in recent years, the mega-basement continues to be a feature that many prime homeowners are keen to implement as it tends to be the only viable option when it comes to adding serious additional space to a home that is otherwise limited in this respect.

“These often multi-story additions are utilised for a range of luxury purposes from swimming pools to cinemas and even wine cellars and it’s clear that they add serious value, whether it’s a property that has already been converted, or simply one offering the ability to do so.