Former MI6 spy lair in Whitehall for sale: bombproof penthouse where James Bond myth was born is on the market for £5.5m

The original Whitehall spy lair where the inspiration for James Bond’s boss M briefed secret agents on thwarting the deadly threat from Germany and Bolshevik Russia is for sale.

The bombproof former headquarters of the Secret Intelligence Service — as well as a pied-à-terre used by its founder Sir Mansfield Smith-Cumming — could become the ultimate home for a very wealthy 007 enthusiast.

The top three storeys of the building where the Bond myth was born have gone on sale for £5.5 million following conversion into a spectacular penthouse apartment.

Legendary spymaster Sir Mansfield moved the new espionage service to Whitehall Court in 1911 shortly after it was founded in response to scares about plots being fomented in Germany against the British Empire.

Its work during the First World War was considered so vital to national security that the eaves of the Portland stone building were reinforced with steel-encased timber beams and hardened flooring to protect it from Zeppelin raids — features that remain to this day.

The former “labyrinthine” warren of offices — so secret that they did not officially exist — was also where real-life “Q” gadget masters developed “toys” such as poison ink pens and bombs disguised as dead rats to be used by agents in the field. It even has a cameo role in the forthcoming Bond movie No Time To Die in which Daniel Craig parks his silver Aston Martin outside the building.

The 4,144 sq ft penthouse is located over the eighth to 10th floors with one of Whitehall Court’s distinctive cupolas providing extra living spaces. The eighth floor has the main reception room opening onto a roof terrace with views over Whitehall. On the ninth floor of the penthouse is the master bedroom suite and two other guest bedrooms.

The 10th floor contains the kitchen and dining room, while the cupola has been turned into a two-level living space with a smaller reception room on the lower level and a library on the top floor. The buyer will occupy the same space where the former Royal

The navy officer signed his memos and reports in green ink simply as C, practices still retained by the head of MI6.

The custom of using only a single letter as a signature was adopted by Bond author Ian Fleming, when he created the character M, most famously played by Dame Judi Dench.

In his SIS memos Smith-Cumming wrote: “Been here five weeks. Absolutely cut off from everyone while here and cannot give my address out or be telephoned to under my own name. One of my colleagues asked me if I should object to his moving into a flat next door, but I told him that I thought it would interfere with my privacy [and secrecy] in my own flat and I told him not to go forward with any such scheme.”

In December 1919 MI6 left Whitehall Court and moved its offices to a house in Melbury Road, Holland Park, although Smith-Cumming continued to use Whitehall Court as his personal office and official residence up until his death in 1923 at the age of 64.

Gary Hersham, founding director of Beauchamp Estates, which is handling the sale, said: “Who doesn’t love the excitement and glamour of the Secret Services, spies, gadgets and James Bond? “Whitehall Court, with its Blue Plaque denoting the founding home of the British secret service is in the heart of the government quarter and within it this unique penthouse, located in the eaves of the building, helps to shine a spotlight on the thrilling history of the secret service and the 007-style agents.”