 The East Tilbury Blockhouse was built partly with stone taken from St Margaret's Chapel in Tilbury, which was dissolved in 1536.Its form is not known but it probably consisted of a brick and stone structure, perhaps in a D-shape, with a rampart and ditch to enclose its landward side.It was recorded as having fifteen iron and brass cannon of various calibres in 1540; these had been increased to 27 by 1539–40.