The London black cab is a purpose-built vehicle driven by someone who has spent years memorising the city. It is one of the few pieces of public transport anywhere that people are genuinely proud of.
The Knowledge
To drive a black cab in central London you must pass The Knowledge of London, introduced in 1865 and effectively unchanged since. Candidates must learn every street within a six-mile radius of Charing Cross — around 25,000 of them — plus 20,000 places of interest, and be able to recite the shortest legal route between any two points from memory.
It takes most people three to four years, studying while riding a scooter around London with a clipboard on the handlebars. Candidates are tested in oral examinations called “appearances”, where an examiner names two points and the candidate must recite the route, street by street, turn by turn, without hesitation.
A famous neuroscience study at UCL found that qualified cabbies have a measurably enlarged posterior hippocampus — the part of the brain associated with spatial memory — and that it grows during training. The Knowledge physically changes the brain.
The vehicle
Black cabs are built to a legal specification. Every one must:
- be wheelchair accessible, with a ramp — all of them, not a special fleet;
- have a turning circle of no more than 25 feet, a rule reputedly set by the roundabout at the Savoy Hotel;
- have room for a passenger to sit upright wearing a bowler hat, an old requirement that shaped the tall roofline.
Passengers sit in the back facing forward with two extra tip-up seats facing them, so five can travel. The driver is separated behind a partition.
Hailing one
If the yellow TAXI sign on the roof is lit, the cab is free — stick your arm out. If it is not lit, the cab is taken and will not stop. Cabs must accept any journey up to twelve miles within London; refusing a fare is a licensing offence.
Fares are metered and rise on evenings, weekends and holidays. Tipping is usual but modest — rounding up to the nearest pound or adding about 10% is normal, and nobody expects American percentages.
Not always black
The name is historical. Cabs were required to be black for decades, but liveries are now permitted and many are wrapped in advertising. The shape, not the colour, is what identifies them.
Cabbies
London cab drivers have a reputation for talking, for firm opinions, and for knowing exactly where they are going. They also cannot be quiet if you would rather they were — though asking directly is entirely acceptable and will not offend anyone.
Note that minicabs and app-based cars are a different thing: they must be booked in advance, cannot be hailed in the street, and their drivers have not done The Knowledge. Getting into an unbooked car that approaches you in the street is illegal and unsafe.