Summer budget 2015: free road tax axed for petrol and diesel carsMorrisons has announced a 2p a litre cut in the price of diesel, making it cheaper than unleaded petrol for the first time since 2001.

The supermarket is the first fuel retailer to respond after the RAC Foundation suggested diesel drivers were being unfairly charged a £250 million premium at the pumps.

The RAC Fuel Watch tool indicated that diesel prices should fall by around 5p a litre in July: Morrisons is the first big retailer to cut pump prices.

The Morrisons price cut at its 336 retailers is live from today (20 July) and a spokesman explained that “because of the recent price drops in the wholesale diesel price, we are able to pass on these savings.

“Many younger drivers won’t remember the last time that diesel prices were lower than unleaded.”

There are nearly 11 million diesels on British roads, a number that has grown significantly in recent years as government VED and taxation policy has incentivised low-CO2 DERV-powered vehicles.

There are 20 million petrol cars on British roads; prices for unleaded at Morrisons will remain unchanged for the time being.