During the Civil War London was fortified by the Parliamentarian forces, a number of forts being erected including a star fort at Vauxhall linked by a chain barrage to Tothill Fields. At Vauxhall the fort was described as a "quadrant fort with four half bulwarks". The workshop at Copt Hall was taken over by the Parliamentary forces. The fort at Vauxhall is known to have survived until the end of the 18th century and is indicated on Lambeth's plan of London, published in 1806, on which it is described as 'Oliver Cromwell's Castle', near to the Effra River at the end of Kent Street.
However, the Royalists never mounted an attack on London and it is doubtful whether the artillery emplaced within the defences were ever fired in anger. One occasion when some of this artillery was fired, in salute, was during the state funeral of the Earl of Essex, commander-in-chief of Parliament�s forces, on 22 October 1646 when, after seven in the evening, a signal was given to the fort in Southwark to fire a great cannon. This was the signal for the next fort, at Vauxhall, to do likewise and so on around the Lines of Communication. This ritual was performed three times. Paragraph source : THHOL, Author : David Flintham