Petrol pump prices could soar by 5p a litre, burning a hole in the pockets of holiday motorists and siphoning nearly £250,000 away from the tourism industry, the AA has warned.
A surge in the wholesale cost of petrol across Europe has already led to a rise in UK petrol and diesel prices, with more misery possibly to come, the AA said.
Northern Ireland, although enjoying the smallest price rise over the past month, is still the most expensive region for petrol at 136.6p. London and north west England are cheapest averaging at 135.5p.
Scotland and East Anglia share the position of most expensive areas in the UK for diesel, both averaging 140.8p a litre and England's north west has the cheapest, at 139.7p a litre.
AA president Edmund King said: "After the price of petrol stabilised at around 134.6p a litre through much of June, and weeks were filled with beautiful weather and sporting excellence, it was perhaps inevitable oil and fuel market speculators would cast a black cloud over what was promising to be a glorious summer."