Fuel prices have risen to an eight-year high amid shortages at filling stations nationwide.
Motoring association the RAC said the average price of a litre of petrol across the UK increased from 135.87p on Friday to 136.59p on Sunday.
Pump prices have not been that high since September 2013.
The RAC warned that the situation could worsen as retailers pass on the cost of rising wholesale prices and a "small number" cash in on panic-buyers.
Drivers this morning reported being charged 154.9p a litre at a forecourt where the advertised price is 134.9p.
One person tweeted: "Texaco A1 advertise £1-39 per litre outside, come to pay and it’s £1-54,99p per litre."
Another told us: "The Langley Vale, Surrey, Texaco petrol station had a sign saying diesel 148.5p on Saturday but they were out of fuel."
Mirror reader Anton said: "My wife was charged £1.50.9 per litre at a BP petrol station in Sydenham today."
Another UK garage increased its fuel prices to 198.9p a litre. despite the average price for unleaded petrol being 134.86p a litre, and 137.35p for diesel.
Has your local garage increased prices to an unreasonable level? Let us know: emma.munbodh@mirror.co.uk
What is happening to petrol prices?
"When it comes to pump prices, it's a pretty bleak picture for drivers," explains RAC fuel spokesman Simon Williams.
"With the cost of oil rising and now near a three-year high, wholesale prices are being forced up which means retailers are paying more than they were just a few days ago for the same amount of fuel.
"This has led to the price of a litre of unleaded already going up by a penny since Friday.
"We might yet see higher forecourt prices in the coming days, irrespective of the current supply problems."
But he warned some independent retailers are cashing in on panic buyers.
"We'd remind drivers to always compare the price they're being asked to pay with the current UK averages which are 136.69p for petrol and 138.58p for diesel," Williams said.
Fuel expert Luke Bosdet at the AA, said it’s not uncommon for retailers to individually increase the price to a) try to deter those topping up their tanks unnecessarily and b) try to recover some of the lost income from drivers buying fuel only and not shopping within the store.
He says the message is clear: "Don’t go to a fuel station at present unless you need to fill up."
In any case, E10 – the new energy efficient unleaded, remains cheaper than E5 by 3p-4p a litre.
“This has provided some cushioning at wholesale level,” Bosdet added.
How much fuel prices have risen in the past week?
Experian Catalist, which tracks forecourt prices, shows petrol prices are climbing:
Monday
Petrol: 135.32, diesel: 137.22
Tuesday
Petrol: 135.59, diesel: 137.18
Wednesday
Petrol: 135.51, diesel: 137.33
Thursday
Petrol: 135.77, diesel: 137.46
Friday
Petrol: 135.90, diesel: 137.62
Saturday
Petrol: 135.83, diesel: 137.99
Sunday
Petrol: 136.69, diesel: 138.58
Is panic-buying necessary?
The UK's biggest operator is the Motor Fuel Group. Other companies include EG - which also owns Asda - along with Esso, BP, Shell, Tesco, Sainsbury's and Morrisons.
Many of these providers say they are struggling, but say the shortages are down to panic-buyers draining all the pumps in one go.
Ministers have called on people to stop "panic-buying" petrol and return to their normal pattern of purchasing as pumps run dry in some forecourts.
Is there a limit on how much I can buy?
EG introduced caps on spending per driver, limiting fuel purchases to £30 in order to support its supply. We’ve got a full list of branches imposing this, here.
A statement by Shell, ExxonMobil and other industry bodies said the pressures on supply were the result of "temporary spikes in customer demand".
Is there enough petrol and diesel to go round?
Yes. There is no issue with the amount of fuel going through refineries.
Oil giant ExxonMobil, which operates Esso forecourts and runs the UK's largest refinery, said it is operating as normal and has "strong supply" to distribution sites.
The problem is getting it to the pumps and reacting to the latest surge in demand.
The rising demand led the Petrol Retailers Association to warn that as many as two thirds of its membership of nearly 5,500 independent outlets were out of fuel on Sunday.
How long will it last?
Forecourt owners will be hoping the initial rush to the pumps will soon ease and supply can get back to manageable levels, although there are warnings it could last for another week.
The advice at this point is to only purchase fuel when you need it.
This should allow the shortage to subside more quickly and will ensure there are enough supplies for emergency workers.
Is there anything I can do to reduce the cost if I have to fill up?
The best advice at this point is to only fill up when you absolutely need to.
When shopping around, bear in mind that fuel stations buy their fuel on the wholesale market. Just as in any other negotiation, the big buyers are better able to strike a deal, so it's worth opting for a bigger retailer.
Also, shop in areas where there are several garages as the competition is likely to be stronger.
When several stations are close together, they are more likely to cut prices to tempt drivers in.
In any case, the website PetrolPrices.com allows you to compare prices in your area. It also lists the latest average prices, so you know if you’re being ripped off.
As a general rule, supermarkets tend to be the most competitive - plus you can collect loyalty points at several of them while you top up.
By contrast, airports and motorways tend to be the most expensive.
