The most expensive petrol stations in Portsmouth as RAC warns of price hike amid fears of panic buying

In response, drivers may be tempted to fill up an extra container or two while prices are still relatively manageable or before they rise further.

After three months of declining pump prices, tensions in the Middle East have triggered a sudden reversal, pushing the average cost of petrol up by 2p per litre, according to new analysis from RAC Fuel Watch.

Unleaded now costs 134.17p a litre on average, up 2p since 1 June, meaning the cost to fill a 55-litre family car stands at £73.79 (£1.07 more than at the start of the month). The price of diesel went up even more – by nearly 3p (2.8p) a litre, from 138.39p at the start to 141.21p at the end. This added £1.55 to the cost a household pays to fill a family car.

Supermarket prices saw below-average increases last month, with petrol up 1.3p from 128.96p to 130.26p, while diesel rose by 1.6p from 135.06p to 136.67p. But it’s once again drivers in Northern Ireland who benefit from the cheapest visits to the forecourt – a litre of unleaded there costs 128p on average, around 6p less than the average across the whole of the UK, with diesel at 134p.

In Portsmouth, the most expensive petrol stations for petrol are 137.9p a litre and 143.9p a litre for diesel, according to petrolprices.com.

Drivers are being warned that storing petrol incorrectly at home could land you with a fine or even invalidate your car insurance if things go wrong.

Graham Conway, managing director at Select Van Leasing, said: “Many drivers are trying to get ahead of rising prices by storing extra fuel at home, but it’s important to understand the risks and responsibilities that come with that.

“Petrol is one of the most flammable substances you can keep at home. Using the right containers and storing it safely can help prevent accidents and protect your insurance cover if anything goes wrong.

“It might be convenient to have spare fuel, but doing it wrong can end up costing far more than you save.”

Here are the most expensive petrol stations in Portsmouth: