Northern Irish registered vehicles in the United Kingdom

English:  Vehicles pictured in the United Kingdom photographed wearing Northern Irish registration plates. For completeness, images in this category should also be categorised by year in one of the appropriate equivalent GB-format branches of the parent category, Category:Vehicles in the United Kingdom by year of registration

In the United Kingdom registration plate system, numbers issued in Northern Ireland have always had different format to those issued in Great Britain. After earlier shorter systems, since 1966 the Northern Irish format has been "AXX 1234", where "XX" denotes the issuing county, the "A" is a serial letter, and the "1234" are serial numbers. The county code always includes either a "Z" or an "I".

As well as being issued to vehicles that stay in Northern Ireland (see Category:Northern Irish registered vehicles in Northern Ireland), it is not uncommon to see a Northern Irish registered vehicles in Great Britain for various reasons (see Category:Northern Irish registered vehicles in Great Britain), not least because it is not possible to tell the age of the vehicle from the plate in the Northern Irish system.

In an analogy to the Q plate in the GB format which is reserved for vehicles with indeterminate age, such vehicles in Northern Ireland are given the code QNI.