Climb to the top of Britain’s only surviving semaphore tower

Peeking just above the trees by the M25 in southwest London can be found a curious octagonal building which was built 200 years ago as part of the defence of Britain.This is the Chatley Heath semaphore tower and is a rare survivor of a series of towers built to send signals to/from London and the coast at a time when an invasion by Napoleon was a very real fear. The construction of the line was ordered in 1816 and was completed in 1822, and it was one of a line of towers to relay signals across