On 10 December 1868, the first traffic lights were installed outside the British Houses of Parliament in London, by the railway engineer J. P. Knight. They resembled railway signals of the time, with semaphore arms and red and green gas lamps for night use. The gas lantern was turned with a lever at its base so that the appropriate light faced traffic. Unfortunately, it exploded on 2 January 1869, injuring the policeman who was operating it.
The above block quote can be found here.
In recent years there has been tendency to make roundabouts rather than traffic lights here. I would guess that is because they are cheaper. Personally I prefer traffic lights. That may be because when I drove, with my driving instructor, to take my test I drove the wrong way round a roundabout. Well I was nervous. I think my instructor was amazed that I passed.