Probably born in Kent in 1744 or 1755, Twiss worked in the ordnance office at the Tower of London from 1760, before becoming overseer of works at Gibraltar. Receiving a commission in the army in 1763. Returning to England, he commenced work on the defences at Portsmouth Dockyard, before accompanying General Sir John Burgoyne's army to Canada in 1776, where he was responsible for a number of defensive programmes. He returned to England in 1783. Over the following years, Twiss oversaw the construction of various defences, including the chain of Martello Towers along the Kent and Sussex coastline. Twiss also accompanied the army on expeditions to the Netherlands, the Channel Islands and Ireland. Twiss was made Major General in 1805, and in 1809 became colonel-commandant of Royal Engineers Cor