April saw the biggest increase in petrol and diesel pump prices for 16 months, with both fuels going up nearly 3ppl.

Data from RAC Fuel Watch shows the average price of a litre of unleaded went up 2.74p from 120.46p to 123.20p. Diesel rose 2.94p per litre from 123.08p to 126.02p.

Not since December 2016 have average fuel prices risen so sharply. The increase then was 3ppl for both fuels, with petrol rising to 117.23ppl and diesel to 119.63ppl. The last time the average price of unleaded was as expensive at it is now was in mid-November 2014. Diesel last exceeded 126ppl on 1 December 2014.

RAC fuel spokesman Simon Williams said: “The dramatic rise in the oil price and its knock-on effect on the cost of fuel is clearly demonstrated by the fact that the four big supermarkets, which sell the largest volumes and therefore buy fuel in more quickly than other retailers, have raised their prices even more steeply. A litre of supermarket petrol went up 3.2p to 120.17p, and diesel by 3.3p to 123p, signifying they are quickly passing on increased wholesale costs to motorists.

“Unfortunately, the price of oil gained $8 in April driven by a combination of international issues, all of which could negatively affect global supply. The biggest of these is the fear that the United States could re-impose crippling economic sanctions on Iran – the third largest oil producer in OPEC – over its controversial nuclear energy programme which it has been limiting as agreed with six world powers, including the US and the UK.

“The outlook for fuel prices is not good at the moment as the oil price is well over $70 a barrel, and if the US does try to re-impose sanctions on Iran and supply drops, motorists will end up paying far more at the pumps. Our current two-week prediction is for prices to go up by a penny or so, but this could quickly get worse if oil gets more expensive and the pound weakens any further.”