Thirteen million motorists have been hit with a 14th consecutive week of fuel price rises.
The average cost of a litre of diesel in the UK has risen to £1.36, according to the latest Government figures.
Prices have increased each week since July 2, representing the longest consecutive streak of rises in more than two years.
Although sales of new diesel cars have fallen in recent months amid concern over emissions, there are still 13 million diesel cars registered for use on UK roads.
Both diesel and petrol prices have spiralled in recent weeks, reaching a four-year high.
Over the past six months the cost of filling up a typical 55-litre family car that runs on petrol or diesel has risen by around £6.
This is linked to oil reaching around 84 US dollars a barrel, compared with 69 US dollars in April.
Recent respite for owners of petrol models appears to be over as the latest weekly data shows the fuel increased by a fraction of 1p per litre to £1.30.
This came after two weeks when price rises were halted due to supermarket price cuts of up to 2p per litre.
Steve Gooding, director of motoring research charity the RAC Foundation, said: “Whilst the drive is on to get people to choose ultra-green vehicles, diesel cars are still on the road in record numbers, and any upward movement in pump prices hits millions of motorists.
“On top of that almost all of the four million vans and half a million lorries in the country run on diesel, and fuel is a major business cost – one that is ultimately reflected in prices on the high street.”