It was commissioned as HMS Birnbeck, and was used for secret weapons development and storage with testing. The "Bouncing bomb" was tested at the Brean Down Fort on the opposite side of Weston Bay. In 1954 the former Axbridge Rural District Council gave of the down to the National Trust to celebrate the Festival of Britain. The Major Aldermen and Burgesses of the Borough of Weston-Super Mare gave in 1963, and a further at Brean Down Cove was acquired from M.D. and M Matthews in 2000. After restoring the fort, which covers , Sedgemoor District Council gave this to the trust as well in 2002. Various proposals have been put forward to construct a Severn Barrage for tidal electricity production from Brean Down to Lavernock Point in south Wales. The proposals, which go back over 100 years, have never been successful so far, however Peter Hain and others are still working on further proposals and trying to persuade the government to fund either the barrage or tidal lagoons. In addition to the geological interest of the site, the range of plants growing on Brean Down has led to it being designated as a Site of Special Scientific Interest. The nationally rare white rock-rose ("Helianthemum appenninum") is a common species at the site, occurring in abundance on the upper reaches of the grassy south-facing slopes. Some of the broomrapes growing here, which were originally thought to be oxtongue broomrape ("Orobanche artemisiae-campestriae"), are now no longer believed to be this species, but atypical specimens of ivy broomrape ("Orobanche hederae"). Other plants on the southern slopes include the Somerset hair grass, wild thyme, horseshoe vetch and birds-foot-trefoil. The northern side is dominated by bracken, bramble, privet, hawthorn, cowslips and bell heather. The birds seen on Brean Down include peregrine falcon, jackdaw, kestrel, collared and stock doves, common whitethroat, common linnet, stonechat, dunnock, rock pipit and – in 2007 – Britain's first and only Atlantic yellow-nosed albatross. There are also several species of butterfly, including chalkhill blue, dark green fritillary, meadow brown, marbled white, small heath, and common blue.