How old do you have to be to be a London taxi driver?

You can apply to TfL and start the Knowledge at 18, but you cannot be licensed until you are 21. There is no upper age limit for starting, and no retirement age: a licensed driver keeps working for as long as they pass their medicals.

Checked against TfL's documents on 3 October 2026.

Starting young

Because the Knowledge takes years, TfL accepts applications from 18, three years before you can hold a licence. A candidate who finishes before turning 21 has to wait until their birthday to start work.

Starting later

There is no upper age limit, as long as you meet the other licensing requirements. Candidates start the Knowledge in their forties and fifties. Bear in mind that it takes most people three to four years, and that the medical standard rises with age: licensed taxi drivers need a medical at 50, 56, 62 and 65, and every year after that.