Proactive Investors - Drivers in the UK paid an extra 6p per litre for fuel last year as supermarkets looked to increase their profit margins, a report from the Competition and Markets Authority (CMA) found.
Asda was also fined £60,000 for failing to provide information to the CMA on two separate occasions.
Fines came when a representative of the retailer met with the regulator but didn’t have the evidence required for the topics being discussed.
Overall, the report found competition got weaker after Asda and Wm Morrison Supermarkets increased the amount of money it makes on fuel sales.
Rivals Tesco PLC (LON:TSCO) and J Sainsbury (OTC:JSAIY) were found to have reacted to the prices of local rivals rather than changes to costs in the market.
No “cartel behaviour” was identified, however, and the CMA is not planning to open an enforcement case against any of the major supermarkets.
While the invasion of Ukraine drove fuel prices last year the regulator found other factors also impacted the increases.
The CMA believe an interactive online service should be created to allow customers to compare fuel prices in real time.
Additionally, it is calling for a new regulator to be formed to monitor fuel prices and develop the fuel price comparison scheme.
Asda is hoping to purchase Co-op petrol stations but in March the CMA expressed multiple concerns that it could lead to higher prices.