The real Slough House: The unlikely homes of MI5
As the popular espionage drama series Slow Horses returns to Apple TV, we look at surprising locations occupied by the real-life MI5 over the years.
Image: Blenheim Palace served as a base for MI5 during World War II | stock.adobe.com
In the wait for James Bond to return to our cinema screens, Apple TV’s Slow Horses has been satiating our appetite for spy thrillers. The acclaimed series is now getting its sixth run of episodes, and sees Gary Oldman’s Jackson Lamb head a team of MI5’s least competent agents.
Watching Slow Horses, you might wonder whether the real-life MI5 would really choose a base as grubby as the fictional Slough House in the series. Let’s just say this: you might be surprised! We at Sky HISTORY certainly were as we cast our eyes over many of the quirky places where MI5 has set up operations.
HM Prison Wormwood Scrubs
Yes, that’s right, MI5 once worked out of a prison. It was very much a case of ‘needs must’, as the agency was rapidly growing in the run-up to World War II. In 1939, many of Wormwood Scrubs’ inmates were transferred to other prisons to make room for MI5 staff.
The agency continued to occupy this West London jail until September 1940, when Blitz bombing laid waste to the site. This calamity prompted Whitehall to move many MI5 employees to an alternative, more remote workplace – Blenheim Palace in Oxfordshire.
Blenheim Palace
Today, this country house deep in the midst of rural Oxfordshire is best known as the birthplace of Winston Churchill. By late 1940, not only was he UK Prime Minister, he was allowing MI5 to adopt his childhood abode as its new wartime base.
Unlike the agency’s former headquarters at Wormwood Scrubs, Blenheim proved safe from Nazi bombing. This wasn’t only down to its far-flung location. German leader Adolf Hitler’s dark vision for the UK included making Blenheim Palace his own private pad. So, he hoped to leave it in tip-top condition for when he intended to triumphantly set foot in it himself.
A former film studio building
We’ve all watched James Bond films and seen them open with that iconic, distinctive roar of the MGM lion. However, you might not have realised that the legendary film studio, which started out in 1924, once provided a home for the actual MI5.
After Nazi bombing rendered MI5’s early wartime headquarters Wormwood Scrubs unusable for intelligence purposes, not all of the security agency’s staff moved to Blenheim Palace. Some instead went to 58 St James’s Street in London, working out of a building formerly occupied by Metro-Goldwyn-Mayer itself. A large ‘To Let’ sign was put up outside to distract from what was really going on inside the property.
Leconfield House
In 1945, MI5 moved into Leconfield House, located on Curzon Street in London’s swanky Mayfair area. The seven-storey office building would remain the intelligence agency’s headquarters for most of the Cold War, with the last agents there only vacating in 1976.
These days, Leconfield House seems to be somewhat stuck in limbo. In 2020, businessman Robert Tchenguiz revealed his intention to turn the site into a 65-bedroom luxury hotel. However, those plans have since been put on ice due to planning disputes. In the mid-2020s, former UK Prime Minister Liz Truss sought to launch a private members’ club at Leconfield House.
Secret garages
It would be too much of a security risk for MI5 agents to have their cars serviced by standard mechanics. So, they were instead directed to a secret, specialised garage at Barnard Road in Clapham Junction. That was until the 1970s, when MI5 learned that Soviet spies were keeping a close eye on the premises.
Though MI5 subsequently switched to a new garage on Streatham High Street, this too was discovered and so is no longer in use. There’s still a secret MI5 garage out there somewhere, but all we know about its location is that it’s in west London.
Thames House
After an 18-year stint at 140 Gower Street from 1976 to 1994, MI5 relocated to its current headquarters at Thames House. The agency had actually been there before in the 1930s, occupying the South Block’s top floor. In the 1990s, though, the site was refurbished to bring it into line with modern operational needs.
Today, you can get a good look at Thames House’s Portland stone exteriors by crossing Lambeth Bridge into Millbank. Such is MI5’s intense need for secrecy, the agency does not permit public tours of the property. However, MI5’s social media pages do provide peeks behind the scenes.
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