Light not so fantastic – 150 years of traffic signals

Today marks the 150th anniversary of the bane of the modern motorist's life – traffic lights.

Actually traffic lights is probably rather underselling the contraption which first appeared outside the Houses of Parliament on December 9, 1869.

Gaslights on the top, and a set of mechanical semaphore arms to draw extra attention, it was more like a giant mechanical scarecrow.

And they certainly scared more than the crows the following month, when an explosion at the base of the semaphore left a policeman with severe burns.

The device, which Punch magazine had likened to a "terrific apparition" seen through the fog, was the invention of railway engineer John Peake Knight.

It represented an attempt to bring order to a chaotic junction between Bridge Street and Great George Street near Westminster Bridge, which had seen two MPs badly injured and a traffic policeman killed.

Based on the railway signals of the day, the lights consisted of a 20ft column with red and green gaslights at the top.

When the lights were on red, for stop, the semaphore arms were raised to the horizontal position, and when they turned to green, the arms were lowered.

They still needed to be operated manually, but the idea was that they would be far more visible than a police officer on point duty.

It is fair to say they were not an unqualified success. Aside from the gas explosion, they were constantly breaking down.

Even when they were working correctly, they just caused confusion, with many drivers unable to understand what the semaphores meant. By the end of 1869 they were removed, written off as just another passing gimmick.

However, the idea did catch on in the United States, with a set installed in Cleveland, Ohio, in 1914, and with the first three-colour system being used in New York in 1918.

By this time, motor vehicles were an increasingly common sight on UK roads, and it was decided that the technology had progressed sufficiently for traffic lights to be reintroduced to London in 1925, at a junction between St James' Street and Piccadilly. These still required manual operation, though, and it was not until 1927 that the UK's first automatic traffic lights were installed – in Wolverhampton.

The lights, controlled by a timer device, were installed at the junction of Princess Street and Lichfield Street on November 4 that year.

Clearly influenced by the American designs, they were suspended across the road by a wire, rather than mounted on a post like modern British lights.

According to reports from the Wolverhampton Chronicle, quite a large crowd turned up to watch the switch-on, although the event turned out to be something of a damp squib.

Within a few minutes, one of the red lights failed, and the policeman was back on point duty.

A few hours later, the operators tried again, and that time they managed to keep them working for a couple of hours, and it was decided to make them a permanent fixture the following year.

They were finally replaced with a more modern system in 1968, but a blue plaque marks the spot where they were.

Today, there thought to be more than 25,000 sets of traffic lights across the UK, and the average motorist will spend six months of their lives stuck behind them.

Still, it is probably a more popular invention than the speed camera.