British racing green, or BRG, a colour similar to Brunswick green, hunter green, forest green or moss green (RAL 6005), takes its name from the green international motor racing colour of the United Kingdom. Although there is still some debate as to an exact hue for BRG, currently the term is used to denote a spectrum of deep, rich greens. "British racing green" in motorsport terms meant only the colour green in general – its application to a specific shade has developed outside the sport.
In the days of the Gordon Bennett Cup, Count Eliot Zborowski, father of inter-war racing legend Louis Zborowski, suggested that each national entrant be allotted a different colour. Every component of a car had to be produced in the competing country, as well as the driver being of that nationality. The races were hosted in the country of the previous year's winner. When Britain first competed in 1902, they had to choose a different colour from the national flag colours of red, white and blue, because those had already been taken for the 1900 race by America, Germany and France respectively. (Italy did not adopt its famous 'Racing Red' until a red Itala won the Peking to Paris race in 1907). When Selwyn Edge won the 1902 Gordon Bennett Cup race for England in his Napier it was decided that the 1903 race would be held in Ireland, at that time a part of the United Kingdom, as motor racing at the time was illegal in Great Britain. As a mark of respect for their Irish hosts the English Napier cars were painted shamrock green.