The introduction of clean fuel at garage forecourts has seen some of the most important environmental changes on our roads over the last two decades.
Motorists first filled up with unleaded fuel twenty years ago. But it nearly didn't happen.
In spite of a "clean air" push by Britain's Prime Minister Margaret Thatcher, with 900 tonnes of lead polluting the atmosphere every year, most of the twenty million vehicle drivers of the day argued that unleaded would destroy their engines.
Finally, in 1988 the government gave way to pressure from environmental groups. Drivers, who refused to switch, faced heavy fines. At the same time Chancellor Nigel Lawson agreed to demands from oil chiefs to raise the tax on four-star by 10p.
Motorists were quick to see the benefit of filling up with cheaper fuel.
Twenty years ago unleaded petrol in the UK cost 165p a gallon. Four-star averaged 171p.
Today's fill-up has already hit £5 a gallon.
Other, more dramatic benefits, such as reduced levels of violence, are being reported since the banning of lead additives in petrol.
Among adults and children, blood levels have fallen in the last twenty years by seventy to eighty per cent. This could halt damage to mental and physical health, and is already justifying clean air campaigns to remove lead from petrol.
