Lists of mountains and hills in the British Isles in England, 366 in Wales and 11 in the Channel Islands. A Simm is a mountain the British Isles that is over high and has a prominence of at least . The word comes from Six-hundred Metre Mountain. There are currently 2,754 recorded Simms in the British Isles, including 2,188 Scottish Simms, 192 English Simms, 149 Welsh Simms, 1 Isle of Man Simm, and 224 Irish Simms. By definition, all Simms are also TuMPs (see below) and most, if not all, are mountains, depending on whether 600 metres or 2,000 feet (610 m) (e.g. a ), is used as the
Introduced species of the British Isles are susceptible. The grey squirrel is a carrier of the squirrel pox virus which kills red squirrels but not grey squirrels. The European crayfish is susceptible to crayfish plague which is spread by the introduced signal crayfish. Unlike some other environmental problems such as pollution, the effect of an introduced species is not a single event. Once a species has been introduced to an island, the problems may persist and escalate as the species spreads further. Coypus "(Myocastor coypus)", large semi-aquatic rodents native to South America, were introduced to the British Isles in 1929 when fur farms were set up