It is being sold by Pastor Real Estate, who describe the property on their website as "a rare opportunity to acquire a delightful one bedroom freehold townhouse."

The house consists of an entrance hall, study, open-plan kitchen and living room, and a bedroom with a small balcony on the top floor. However, at just 726 square foot for the whole house, the rooms are far from spacious.

The head of sales and lettings at Pastor Real Estate, Susan Cohen, said "This is a unique opportunity to own the smallest mews house currently on the market in Mayfair.

"The freehold property is situated in a charming quiet cobbled street in the heart of Mayfair, making it ideal for those looking for a quirky pied-a-terre."

The house is on sale as part of a freehold - meaning you buy the property outright, rather than purchasing a long-term lease, which is common in the UK property market today - which accounts in part for the high cost.

The average home in the UK costs around £250,000 - seven times lower than the price of the Mayfair townhouse, and the average size for a UK house is 818 square foot.

In a different area of the UK the £1.8 million price of the "pied-a-terre" mews house could buy a seven bedroom mansion in Lincolnshire, complete with a home cinema, or a eight-bedroom house in Ayrshire, Scotland, with its own golf course.

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The UK's most expensive 1 bedroom house: £1.8 million Mayfair property costs seven times the average home