Pewit Island is a small island located in the north western section of Portsmouth Harbour.[1] Historically it appears to have been connected to the mainland via a manmade shingle causeway, parts of which still exist.[1] The island has been colonised by oak and blackthorn scrub.[2]The island is a Hampshire and Isle of Wight Naturalists’ Trust nature reserve.[2]
In 1857 plans drawn up to improve the defences of Portsmouth included building a fortification on the island.[3] The plans were latter modified in the face of improved artillery technology and the fortification was never built.[3]