Quirky, independent and defined by the Thames Estuary, Canvey lies on the north bank of the Thames between Basildon and Southend on Sea, just 25 miles from London. Most of the island lies below sea level and, despite being the fourth most populated island of England, it has a surprising amount of open space and two important nature reserves. Wild marshes, ancient inns, arty promenades and music royalty make a great day out from London.