List of country codes on British diplomatic vehicle registration plates
This is a list of country codes on British diplomatic car number plates, i.e. the first group of three numbers. 
Since 1979, cars operated by foreign embassies, consular staff, and various international organisations have been given number plates with a distinguishing format of three numbers, one letter, three numbers. The letter is D for diplomats or X for accredited non-diplomatic staff. The first group of three numbers identifies the country or organisation to whom the plate has been issued, the second group of three numbers is a serial number, starting at 101 for diplomats (although some embassies were erroneously issued 100), 400 for non-diplomatic staff of international organisations, and 700 for consular staff.
Many foreign embassies have acquired personalised plates from historic British car numbering systems, for example, CAN 1 (Canada), AUS 1 (Australia), BEL 12E (Belize), BF 1 and BF 2 (Burkina Faso), CHN 1 (China), FIJ 1 (Fiji), FRA 1 (France), 1 HKG (General-Director of Hong Kong Economic and Trade Office), IC 1 (Iceland), 1 NWY (Norway), etc..