10 December 1868: world's first traffic lights installed in Britain

The next time you're stuck at the traffic lights, spare a thought for the poor policeman that copped it as a result of the world's first traffic signals, installed outside the Houses of Parliament on 10 December 1868.

Two years earlier, a House of Commons select committee had been tasked with bringing order to the traffic clogging up London's roads. As part of its enquiries, it interviewed John Peake Knight, who was the superintendent of the South Eastern Railway. It was his suggestion that the city's long-suffering traffic policemen, who were hard to see above the hubbub, should be replaced with semaphore signals – tall pillars with movable arms that told road users when to stop.

The first (and as it turned out, only) road pillar to be installed was built by railway engineers Saxby and Farmer, and stood 24 feet tall with four-feet long, scarlet-red arms. Red and green gas lights were added to provide visibility through the night and the London smog. The Engineer magazine described the "handsome semaphore signal post, installed at the junction of Great George Street and Bridge Street, as having been "uncovered after the manner of an inaugurated statue". 

A policeman was still required to operate it, but raising and lowering of the arms could be carried out "without any strain or effort". Even "a lady or youth" could do it. Yet while it may have been easy to operate, it was still extremely dangerous.

A report published in The Times on 6 January 1869 noted that the "roadway round the pillar has smelt of gas almost from the time the pillar was put up, as if it was soaked with gas". Explosions were not uncommon. And one night, the constable on duty – unaware that gas had been slowly leaking into the pillar's hollow column – opened the box. The flame at the top ignited the gas,which exploded, killing him. The semaphore signals were taken down and the idea was shelved until 1929, when traffic lights returned to the capital.