SUPERMARKETS have increased the price of petrol and diesel every day since the end of March, a new analysis shows.

More than eight pence per litre was added to average pump prices between March 26 and May 23 at the big four supermarkets, RAC Fuel Watch data shows.

The rises are due to the price of oil increasing to more than 80 US dollars, combined with a weakening of the pound.

Average UK forecourt prices currently stand at 128p per litre for unleaded and 131p for diesel.

This is the most expensive both fuels have been since October 2014.

Petrol prices in Christchurch are among the highest in Dorset, with the cost of unleaded a staggering 135.9p and diesel 1p more.

In comparison, a few miles away in Bournemouth the equivalent prices at Tesco Extra off Castle Lane East are 124.9p for unleaded – one of the cheapest prices in Bournemouth – and 130p for diesel.

Motorists in search of the least expensive fuel will need to head to Asda in Canford Heath, where diesel currently costs 127.7p, and Tesco stores in Branksome and Bournemouth where unleaded stands at 124.9p.

Murco in Wimborne is also charging 124.9p for petrol, while Sainsbury’s in Alder Road, Poole is offering some of the cheapest diesel at 127.9p.

However, RAC fuel spokesman Simon Williams said the outlook for fuel prices in the weeks ahead was “not good”, with another penny a litre expected to be added.

“This is the worst series of consecutive daily supermarket price rises we have seen since we began monitoring this three-and-a-half years ago,” he said.

“The supermarkets are being very quick to pass on increases in the wholesale price of fuel. They are far faster at passing on rises than falls.

“All we can do is hope the international forces - which have caused the oil price to rise - ease and take the heat out of prices on the forecourt.”

He added motorists should think about changing their driving styles in the meantime to improve fuel economy. This includes avoiding harsh acceleration and braking and keeping vehicles moving at more constant, slightly slower speeds.

Meanwhile, fuel duty would be cut by a fifth under a radical scheme to change the way roads are paid for. Drivers would save 14p per litre under the Road Miles concept, which was developed by AA president Edmund King alongside his economist wife, Deirdre. It would see drivers charged for every mile they drive over 3,000 miles per year.

Motorists would pay less than 1p per mile in the first year and there would be concessions for those living in the most rural areas and the disabled, according to Mr King.

The amount of revenue generated would lead to fuel duty being reduced from 70p per litre (including VAT) to 56p over five years.