Key Points:

Petrol prices fell yesterday by 5c a litre, but diesel remains at last week's level of 125.9c.

The four big oil companies dropped 91-octane petrol at main-centre sites to 157.9c, but were undercut as usual by Gull, by 1c for mineral fuel and 3c for biofuel.

Petrol is now 15c cheaper than at the start of last week, taking it to its lowest level since October last year.