Supermarkets increased their fuel prices more than the market average in December and motorists began 2018 paying the highest price for unleaded petrol since the end of 2014, RAC Fuel Watch data reveals.

An analysis of fuel prices for December shows the average price of unleaded petrol increased for the second month running – this time by half a pence from 120.66ppl to 121.11ppl, while diesel went up from 123.06ppl to 123.46ppl. A litre of unleaded petrol is now at its highest point since 2 December 2014.

Fuel prices at the four big supermarkets went up by more than half a pence a litre in December with petrol rising from 117.26ppl to 117.84ppl and diesel from 119.69ppl to 120.34ppl.

The price rises have been driven by the increased cost of oil which is at its highest level since May 2015 at $66.61 – the cost of a barrel rose 3% in December having started the month at $64.59.

RAC fuel spokesman Simon Williams said: “Sadly, December was the month oil reached its highest point for over two and a half years – something which motorists are now feeling the effect of at the pumps.

“On a brighter note, the shutdown of the North Sea Forties pipeline did not cause the price of oil to increase as many expected. It had been feared this would lead to petrol and diesel going up in the run-up to Christmas, but luckily for drivers global oil production was not negatively affected as a result.

“It’s hard to see pump prices getting much cheaper in the early part of 2018. The times of lower cost fuel appear to be over and it’s probably now far more likely that we will see them going up as OPEC’s oil production cuts are starting to have the desired effect of reducing the global oil glut and pushing the barrel price higher.”