The Western Heights of Dover are one of the most impressive fortifications in Britain. They comprise a series of forts, strong points and ditches, designed to protect the United Kingdom from invasion. They were created to augment the existing defences and protect the key port of Dover from both seaward and landward attack. First given earthworks in 1779 against the planned invasion that year, the high ground west of Dover, England, now called Dover Western Heights, was properly fortified in 1804 when Lieutenant-Colonel William Twiss was instructed to modernise the existing defences. This was part of a huge programme of fortification in response to Napoleon's planned invasion of the United Kingdom. To assist with the movement of troops between Dover Castle and the town defences Twiss made his case for building the Grand Shaft in the cliff: