Asda was the first to say it was making reductions, cutting the cost of petrol and diesel by 2p a litre from Tuesday.
Then Sainsbury's and Morrisons followed suit and, finally, Tesco said that it, too, would be cutting fuel prices by up to 2p a litre from Tuesday.
AA president Edmund King said: "Drivers will welcome the latest fuel price reductions at the pumps. Prices of petrol and diesel both crept up around 1p a litre last month.
"Our June fuel price report revealed that retailers had on average this year been charging at least a 1p per litre extra on diesel. Hence we believe that all retailers should look to cut fuel prices to reflect the market price at the pumps.
"For the past six weeks, retailers have been paying 2p-3p more a litre for diesel compared to petrol. Yet, when they sell it to drivers, diesel is typically around 4p more expensive than petrol. The AA advises that diesel prices vary locally more than petrol so drivers should search out diesel-friendlier forecourts."
"But in historical terms they are still stubbornly high and the litre price of petrol has not been below 130p since March 2011."