Supermarkets are cutting fuel prices just days after official figures showed sharp increases at the pumps had helped pushed inflation to a three-and-a-half year high.
The cuts come after a barrel of Brent crude slipped below $50 this week for the first time since November on latest concerns about a global glut of supply due to US production levels.
Tesco, Britain's biggest supermarket, said it was cutting the cost of petrol and diesel by 2p per litre at all of its 500 petrol stations on Friday afternoon.
Sainsbury's said it was cutting prices by 2p from Saturday at its 306 forecourts.
Asda said it was cutting up to 2p per litre of fuel at its 301 sites on Saturday, capping prices at 112.7p for unleaded and 114.7p for diesel.
Morrisons also said it was reducing prices by up to 2p per litre at its 333 filling stations.
AA spokesman Luke Bosdet said the cuts were welcome, though the falls in wholesale prices had been "slow to work their way through to the pumps" except in towns where there were "strongly competitive supermarkets".
He said: "The past has shown that, when they cut prices across the board, it brings UK average prices down significantly.
"Our main concern will be with prices in small market towns without a supermarket presence.
"They very often become the land that fair prices forgot."
It is the second set of price cuts at supermarket filling stations this month.
The announcements come after the Office for National Statistics said inflation had risen to 2.3% in February,