What is a ‘Butter boy’ in the London taxi trade?

In the London taxi industry, the term ’butter boy’ refers to a newly licensed taxi driver who is still learning the trade and lacks experience.

The term is typically used by veteran taxi drivers to describe the drivers who are just starting out in their career as taxi drivers. The label can stick with a driver until they renew their licence for the first time which lasts a three year period.

The origin of the term ’butter boy’ is not entirely clear. However, it is believed to have originated from the practice of spreading butter on a slice of bread. In this context, the term implies that the newly licensed driver is still "fresh" or "soft", similar to how butter is soft and easily spreadable. It suggests that the butter boy lacks the hardened experience and knowledge that comes with time and practice in the taxi industry.

There’s also the theory, and it‘s my preferred one, that the term means the driver is just ‘but-a-boy’ when it comes to knowing the industry.

Either way and whatever the theory, the term is used for cabbies fresh out of the Knowledge of London and behind the wheel of a black cab.