Fuel prices have risen for an eighth successive week to reach a four-year high.
The average cost of a litre of unleaded stands at more than £1.29 at UK forecourts, with diesel exceeding £1.33, Government figures show.
Unleaded has not been this expensive since August 2014, while the price of diesel last reached its current level in September of that year.
Steve Gooding, director of the RAC Foundation, warned that families embarking on domestic breaks and day trips are being hit by the rising cost of refuelling their vehicles.
He said: “These latest price increases will not have been lost on the millions of motorists travelling the length and breadth of the country in the past week or so heading to and from holiday destinations.
“The cost today of filling an average car with diesel is £8 more than it was a year ago and it is a similar picture for petrol.”
Mr Gooding went on to predict that the increase in fuel costs will lead to higher prices for consumers.
“The impact isn’t just felt by drivers,” he said.
“Fuel is a significant cost to many businesses and inevitably any increased burden will be passed on to customers through higher priced goods and services.
“While rising oil prices and a weaker pound are contributing to what happens at the pumps it’s worth remembering that, despite the fuel duty freeze, more than 60% of what drivers pay still goes to the Treasury.”