UK average petrol prices fell by almost 7p in September, bringing a typical tank of unleaded below £90 for the first time since May. That’s according to the RAC’s Fuel Watch initiative, which says prices would have fallen further had retailers dropped prices to match the reduction in oil prices.

The RAC says the price of the average litre of petrol has fallen by almost 29p since its peak on July 3, and a typical 55-litre fill-up has now dropped below the £90 mark. That means drivers are saving an average of almost £16 per tank compared with July’s prices.

Similarly, diesel prices also fell in September, finishing the month 3.5p per litre cheaper. That’s 19p below the peak price of 199.09p the RAC recorded on June 25, while the price of a typical 55-litre tank has fallen below £100 for the first time since late May.

Man at petrol station filling up

Despite all this, the RAC maintains that pump prices could still be lower. According to the organisation’s fuel spokesperson, Simon Williams, the wholesale cost of fuel – the amount retailers, as opposed to customers, pay – was around 120p per litre for the entirety of last month. Given retailers usually make a profit of 7p per litre, the RAC says the average current margin is around 17p per litre.

“Despite September seeing the sixth biggest ever drop in the price of petrol, drivers really should have seen a far bigger drop as the wholesale price of delivered petrol was around 120p for the whole month,” said Williams.

“This means forecourts across the country should have been displaying prices around 152p given the long-term margin on unleaded is 7p a litre. In stark contrast to this, RAC Fuel Watch data has shown margins to be around 17p a litre – a huge 10p more than normal. And the average price of petrol at the big four supermarkets is only 1.5p lower than the UK average – less than half what it usually is which points heavily to them not playing fair with drivers.”

“However, as many drivers will have noticed, there are lots of smaller forecourts which are now selling fuel much cheaper than the supermarkets. We would urge everyone to shop around for the best deals rather than simply assuming the supermarkets are the lowest because they have been in the past. And despite the plunge in the value of the pound, the fact oil is trading under $90 a barrel should lead to better prices at the pumps if only more retailers would pass on the savings they’re currently getting every time they buy new stock.”