The average price of a litre of diesel has hit a high of just over £1.80 a litre – and could rise even further if the EU ban on Russian oil goes ahead.

The RAC reported that the price a litre in the UK has outstripped the previous record of £1.79, set in March after Moscow’s invasion of Ukraine.

The amount paid on forecourts had dipped in the interim but began rising again in recent weeks as efforts to hit the Kremlin economically fed through into already high fuel prices. A full EU ban on Russian energy imports could push this even higher.

High diesel prices are a warning sign for the economy as the fuel is typically used in vans and lorries owned by businesses, driving up their costs.

The RAC said petrol prices were also rising – up 3p since the start of the month at 166.65p on average, a penny shy of the record high set in March.

Campaigners said the price rises had rendered ineffective the 5p fuel duty cut announced by the chancellor, Rishi Sunak, in his spring statement in March.

The RAC’s fuel spokesperson, Simon Williams, said: “Unfortunately, drivers with diesel vehicles need to brace themselves for yet more pain at the pumps. Had Mr Sunak reduced VAT to 15% as we call on him to do instead of cutting duty by 5p, drivers of diesel vehicles would be around 2p a litre better off, or £1 for every full tank.

“As it is, drivers are still paying 27p VAT on petrol and 29p on diesel, which is just the same as before the spring statement.”

Williams added: “While the wholesale price has eased in the last few days, this is likely to be temporary, especially if the EU agrees to ban imports of Russian oil.”

EU diplomats are reportedly still aiming to agree a phased embargo on Russian oil this month.

The Office for National Statistics said last week that prices at the pump were contributing to the cost of living crisis as it revealed that the UK’s economy shrank 0.1% in March.