It comes after concerns that the 5p cut announced by Chancellor Rishi Sunak in his Spring Statement in March is still not being reflected in pump prices at all filling stations. The government said companies failing to do so could be “named and shamed”.

RAC fuel spokesperson Simon Williams said: “It’s a truly dark day today for drivers with petrol now crossing the thoroughly depressing threshold of £100 a tank (£100.27p). A complete diesel fill-up now costs £103.43.

“With average prices so high – 182.31p for a litre of unleaded and 188.05p for diesel – there’s almost certainly going to be upward inflationary pressure which is bad news for everybody.

“While fuel prices have been setting new records on a daily basis, households up and down the country may never have expected to see the cost of filling an average-sized family car reach three figures. With RAC research showing as many as eight-in-10 depend on their cars many must be wondering if any further financial support from the Government will be forthcoming.

“March’s 5p fuel duty cut now looks paltry as wholesale petrol costs have already increased by five-times that amount since the Spring Statement (25p). A further duty cut or a temporary reduction in VAT would go a long way towards helping drivers, especially those on lower incomes who have no choice other than to drive.

“It’s also important to remember that the Government is still benefitting from the high fuel prices by taking around 30p in VAT from every litre sold. This compares to just 25p before Russia invaded Ukraine. On top of this the Government is still collecting 53p fuel duty from every litre.

“Other price records were also unfortunately set on Wednesday as the average of a litre of unleaded at a supermarket jumped 2.5p to 175.91p while diesel increased by nearly 2p to 184.13p. As we expected, other supermarkets raised their prices yesterday in line with the increases made by Asda.”

The Prime Minister’s official spokesman said they were continuing to look at all possible options, adding: “Transparency may have an important role to play.

“It is important the public understand what actions each of the fuel retailers are taking and so we are considering what further options we can take in this area.

“We know that there has been variation in that and we do want to see it passed on at all petrol stations. We are not confident that that is happening across the board,” the spokesman said.

“The CMA have said that if they find evidence that the cut is not being passed on that would mean competition is not working and they could launch a formal investigation. Obviously we would wholeheartedly support them.”