That difference has now effectively been wiped out by Mr Brown's tax cut. Low sulphur fuel is essentially cleaner for the environment and better for engines. The chemical reduces the efficiency of catalytic converters and also blackens buildings. The AA says motorists may already be filling up on ULSP without knowing, and it doesn't affect engine performance. However, it's not all good news.
Environmentalists say low sulphur fuels do nothing to combat climate change issues.
It is even claimed the fuel has slightly higher emissions of carbon dioxide - the greenhouse gas that is often blamed for global warming. It is also argued that sulphur particulates in the atmosphere mirror the sun's rays and so mitigate global warming. While low sulphur petrol pumps are absent from most filling stations, the fuel is set to become widely available in coming months. The supermarkets have led the way by introducing ULSP to their forecourts.