Both petrol and diesel prices increased in August, meaning that prices have gone up for eight of the past 12 months and making both fuels 13ppl more expensive than this time last year, according to RAC Fuel Watch.

The average price of a litre of unleaded petrol increased by 1.65p to 130.59p and diesel went up 1.32ppl to 132.19ppl in the month. A year ago, however, petrol was 117.51ppl and diesel was 118.37ppl.

The price of petrol in the UK is now at its highest since the end of July 2014 just before the price of a barrel of oil began to plummet and diesel is at its most expensive since the beginning of October the same year.

However, the figures leading to these prices are very different. At the last peak oil was $106 a barrel and the pound was worth $1.70. At the end of this August oil finished at $77.54, while sterling was only worth $1.29, which means both petrol and diesel are far more expensive to buy on the wholesale market. So despite the lower oil price, the substantially weakened pound has caused fuel prices to reach their highest levels for the last four years.

RAC fuel spokesperson Simon Williams said: “August was another bad month for motorists and it’s rapidly becoming a horrible year on the UK’s forecourts and it looks like further increases are inevitable. Having benefitted from some very low prices two and a half years ago drivers get a nasty shock every time they go to fill up their cars, having to fork out more and more.

“With the pound at such a low against the dollar, and fuel being traded in the US currency, it will only take a moderate rise in the price of oil for some eye-wateringly high prices to be seen at the pumps.

“With many factors at play on the global oil market the price of a barrel could easily break through the $80 mark and stay there. If this were to happen it would be dire news for drivers and we could even see pump prices heading towards the record highs of April 2012 when petrol hit an average of 142p a litre and diesel 148p.”