Last year, he announced plans to classify the performance of English hospital trusts using a simple traffic-light system of green, amber and red.

ECONOMIST: Hospitals

You will have your own favourites, but I always liked the Traffic Light Tree in London's Docklands, a bewildering display of red, amber and green which kept me waiting, transfixed and tense, for really quite some time when I first encountered it.

BBC: Sheep on Shoreham roundabout

It said it wanted a "traffic light" warning system for drugs - with green for those safe to take and drive, amber for caution and red signalling severe adverse effects which would dangerously impair driving.

BBC: You are in: UK