This punchy warning to motorists is a memorable example of the simple, take-no-prisoners school of public information warnings. Using a fist and an open palm, actor Edward Judd (in the tight roll-neck jumper that was a symbol of no-nonsense masculinity in the late 1970s), demonstrates the impact of a collision between a car and a motorbike at a junction. Some alarmingly convincing simulated crash footage helps hammer in the message.

"Think once... think twice... think bike!"