A collapse in the price of oil to the lowest level this century is not being passed on to motorists in full.
The AA reports petrol prices have fallen 11p a litre in the past month, but the wholesale cost of fuel has dropped by much more than that.
Once tax and fuel duty have been factored in, the AA calculates that under normal circumstances petrol prices should now be about £1 a litre.
In fact, petrol is trading at 110.40p a litre and diesel at 115.64p.
AA fuel price spokesman Luke Bosdet said: “Those representing the retailers say that pump prices need to stay high in the lockdown to compensate for lower sales volumes and avoid forecourt closures."
On Monday a barrel of WTI Crude oil was trading at $14.85 - its lowest level since 1999.
Russ Mould, investment director at AJ Bell, said: "Oil is still one of the main fuels for a global economy which is effectively off the road while countries look to contain the coronavirus.
“As a result there is too much supply to meet current levels of demand and oil producers’ cartel OPEC and its affiliates are not cutting production quickly enough.
"The reality is that they probably couldn’t even if they wanted to."
That oil price drop means wholesale petrol prices have fallen 16p a litre - or 19.2p a litre once VAT is factored in - far more than the 11p drop in prices to customers.
However, not all parts of the country have seen drops of the same size - with Northern Ireland, Scotland and Wales seeing far lower prices than London and the South East, for eample.
Bosdet said: "It is likely that once Covid-19 is defeated there will be calls for a review of UK pump prices during the current oil and commodity fuel price crash, as there were in the years after the 2008 to 2012 price spikes.
"One of the questions will be whether it is purely coincidental that Northern Ireland with an effective consumer watchdog has the lowest pump prices in the UK?”
