It’s the classic Sherlock Holmes-era image of London: hansom cabs clip-clopping all over the city with the proud driver or “cabbie” holding the reins whatever the weather. But in a city known for rain and the occasional pea-souper, where could these men go for a cup of tea?

Even though it was against the law to leave their horse and cab unattended at a stand, the pub was too often the only option for wet, wearied cabbies to seek refuge from the dreary weather. So in 1875, the Earl of Shaftesbury and others formed the Cabmen’s Shelter Fund.

More than 60 cabmen’s shelters—boxy green huts only allowed to be the size of a horse and cart—appeared throughout the city over the next few decades. The sheds finally gave drivers a place to rest and hunker down with a hot meal. Even to the most streetwise Londoner, these huts were unknown territory open only to cab drivers possessing “the knowledge” of central London’s countless streets and points of interest. About a dozen cabbies could cram inside a single shelter.

There are only 13 left today, all of which are Grade II listed protected buildings. Many of the other shelters still serve their original purpose, letting taxi drivers pop in for a hearty British meal. On a miserable day there could be a dozen or so drivers crowded inside, though bad behavior is strictly forbidden (no gambling, drinking, swearing or discussion of politics).

But nowadays, these huts aren’t solely reserved for drivers, though non cabbies aren’t actually allowed inside. Though several personalities have managed to work their way in, including: Winston Churchill, Benny Hill, Paul McCarthy, and Frank Sinatra. If you keep a careful eye out for the small open hatch (and signs), you can get a takeaway coffee, bacon sarnie, or other delights at the “Little Green Hut” in Russell Square. The general public can stand on raised steps, give their orders, and catch a glimpse of the newspaper-covered table and benches inside.

Dedicated in 1901, this particular hut was originally located in Leicester Square, the heart of the theater district (Sir Squire Bancroft was a noted actor-manager). It was moved later to a location just a couple of blocks from the British Museum, and restored in 1987 (though the horse troughs that used to be outside were sold off years ago). The black metal railings that run along the sides were initial used as posts to tie up the horses.