Captain Shannon by Coulson Kernahan

No one who has not visited Canvey would believe that so lonely and out-of-the-world a spot could exist within thirty miles of London. Just as we sometimes find, within half-a-dozen paces of a great central city thoroughfare, where the black and pursuing streams of passengers who throng its pavements never cease to flow, and the roar of traffic is never still, some silent and unsuspected alley or court into which no stranger turns aside, and where any sound but that of a slinking footstep is seldom heard, -- so, bordering the great world-thoroughfare of the Thames, is to be found a spot where life seems stagnant, and where scarcely one of the thousands who pass within a stone's throw has ever set foot.

Where the Thames swings round within sight of the sea, there lies, well out of the sweep of the current, a pear-shaped island, some six miles long and three miles broad, which is known as Canvey.