Asda has reduced the price of petrol to its lowest level since February.
The supermarket chain said its 192 filling stations would charge no more than 128.7p a litre for petrol and 136.7p a litre for diesel.
Transport costs includingcar insurance premiums continue to be the main cost pressure on households, according to Asda's income tracker.
It calculates the typical British family is £15 a week worse off than this time last year.
Sainsbury later responded by announcing its intention to cut fuel prices by up to 2p a litre in many of its stores.
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