The PRA has warned that the price differential between diesel and petrol is set to increase and urged the Chancellor not to penalise diesel drivers with higher duty levels in November’s Budget.

PRA chairman Brian Madderson said: "The outlook for UK pump prices remains uncertain with changes to crude oil prices and exchange rates hard to predict, but it does look as though diesel will continue ahead of petrol.

"Some forecasts suggest the ’demonisation’ of diesel will reduce demand in the mid-term, but to create an even greater differential by increasing diesel duty further in November’s budget would have damaging consequences for the economy, in particular by raising the cost of transporting goods by van and truck."