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 damage. Case studies of impact examples can be found at the Non-native Species Secretariat website. Information on control methods for aquatic species can be found at the GB Non-native Species Secretariat website. One notable example of a species introduced to the British Isles is the grey squirrel from North America, which out-competes the smaller native red squirrel, as well as carrying a virus that is fatal to the reds. The cost of attempting eradication was reported in 2010 to be £14 million. These attempts have been deemed unsuccessful and priority is now being given to preserving the remaining red squirrel