Fuel retailers have been accused of refusing to pass on Chancellor Rishi Sunak's duty cut in full. Mr Sunak used his spring statement on March 23 to reduce fuel duty by 5p per litre.
That was worth a saving of 6p per litre owing to the impact on VAT. But the average price of a litre of petrol at UK forecourts has fallen by just 3.7p per litre.
Figures from data firm Experian Catalist show the average price per litre on Sunday was 163.6p, compared with 167.3p on March 22. The average price of diesel fell by 2.4p per litre over the same period, from 179.7p to 177.3p.