This is a list of P600 mountains in Britain and Ireland by height. A P600 is defined as a mountain with a topographic prominence above 600 m (1,969 ft), regardless of elevation or any other merits (e.g. topographic isolation); this is a similar approach to that of the Marilyn, Simms, HuMP and TuMP British Isle mountain and hill classifications. By definition, P600s have a height above 600 m (1,969 ft), the requirement to be called a "mountain" in the British Isles. The "P" terminology is an international classification, along with P1500 Ultras. P600 and "Majors" are used interchangeably.