Weaker pound could see petrol prices rise by 8p per litre within weeks after Brexit vote

British motorists could see their petrol costs jump by an extra £125 a year, as the UK's Brexit vote continues to put the pound under pressure.

Petrol prices are predicted to rise by 5p to 8p per litre when forecourt stocks are refilled in two weeks, a source close to a major supermarket retailer told IBTimes UK.

"The maths on this are pretty simple," said the retail source. "The average household buys 30 litres of fuel a week. At the upper end of the scale that around £125 extra a year a family will spend on petrol at a time when household budgets are being squeezed."

Since the UK's vote to leave the European Union last week, the pound suffered its steepest monthly fall in June versus the dollar since the height of the global financial crisis in October 2008.

The British currency fell 8.6% in June, making it the pound's fourth worst month on record. Motorists have been enjoying lower pump prices in recent months as the result of oil prices roughly halving over the past two years from above $100 a barrel to less than $50 today.

But that may change as the weaker pound means that buying crude oil, which is priced in dollars, becomes more expensive.

Unleaded petrol rose 1.9p to 109.2 per litre in May compared to the month before, according to the AA motoring body. Diesel prices jumped 2.2p to 109.1 per litre in the same period.

The AA predicts a petrol rise of between 2p and 3p over the coming weeks.