Petrol prices are poised to break through the key psychological barrier of £1 a litre.
The AA fears a rise in duty will inflame diesel prices
The Middle East conflict has pushed the cost of crude oil to record highs, with prices threatening to top $80 a barrel.
Diesel prices hit an average of 98.93 pence a litre on Sunday while unleaded petrol hit a record price of 97.02p.
A top motoring body has called on the government to freeze petrol tax to prevent pump prices breaking the £1 a litre barrier.
Call for calm
Petrol tax tracks inflation and is set to increase on 1 September.
The AA Motoring Trust said a decision on fuel duty had to be taken within the next week before the beginning of Parliament's summer recess.
The Trust's Ruth Bridger warned that panic buying triggered by the Middle East conflict could create a serious petrol shortage.
She said that motorists rushing to fill up their tanks would unbalance the UK's normal chain of petrol distribution.
"The worst thing that can happen now is panic buying. If motorists keep topping up their tanks the whole infrastructure will be thrown out of sequence", Ms Bridger said.
The current record price for diesel was 99.19p a litre on 4 May, according to forecourt analysts Catalist.
Even prices hovering just under £1 a litre may not reflect the full impact of the Middle East crisis, according to Ms Bridger.
"The current prices reflect worries over Iran and the beginning of the US summer driving season filtering through from June", she said.
The Trust advises motorists to drive more economically, avoiding hard acceleration and reducing speeds to cut overall petrol consumption.
The sudden surge in petrol pump prices triggered by the Middle East crisis will not last, an oil industry body said.
Chris Hunt, director of the UK Petroleum Industry Association, said the high cost of petrol was "short-term and purely speculative".
Oil production levels have not been altered by the conflict, he said, so any resolution of the crisis would dampen prices.
The following comments reflect the balance of opinion we have received:
Already prices have started to rise in our area. Last week, diesel was selling for 94.9p, yesterday it was 97.9p. I've seen diesel for 99.9p at one station on the A2!
Sukhdeep Rehal, Bexleyheath, UK
Catalist are wrong in their assessment. In West Sussex our diesel prices are already 99.9p a litre and it has been at this level, or near to it,for some time.
Fuel prices in France are higher than they were but are still 20 - 25p a litre cheaper than the UK.
Richard Griffiths, United Kingdom
We are paying £1.02 a litre for unleaded and £1.04 for diesel here - an absolute disgrace yet you would think it was 10p a litre, with the amount of luxury cars and 4x4s on the Island.
Paul, Douglas, Isle of Man
I paid 108p for a litre of petrol at a filling station in Brighton this morning....quite put me off my breakfast.
Nick Bowman, Brighton
I filled up today at East Midlands airport and paid 104.9p per litre of diesel. It's about time the government lowered fuel duties on all fuels.
John McPhee, Derby
We have been paying 99.9p for diesel for months now petrol has been hovering around the 94/95p mark for the same length of time. When is this going to stop?
Robert, Newtownabbey, N. Ireland
104p in the North of Scotland. We have been paying over £1/litre for at least the last 6 months.
David Wilson, United Kingdom
I paid 99.99p per litre for diesel yesterday (Sunday) and as I use my car to go to and from work, clocking up around 600 miles per week it becomes quite expensive.
Tony Burns, Lancs
I have paid £1.02 a litre for diesel at a BP Station just outside Sawston in Cambs about 4 weeks ago. Most garages in the East Kent region are at 99.9. and have been for weeks.
Gary Thomas, Rochester, Kent
We've already been paying over the average for petrol in North Devon now for a while - the cheapest for unleaded is 98.9 with diesel costing 99.9 a litre. The petrol station across from my office has both at 99.9p. How come no one is on strike this time around?
Kath, Braunton, North Devon
I drove from Newcastle to London yesterday and there were quite a few petrol stations already charging £1 for a litre of petrol.
Chris Phillips, England
Cardiff has had petrol and diesel at 99.9p all weekend at the garages of Texaco on one of the main roads into the City centre.
Brendan, Cardiff, Wales
I worked for BP in the UK in 2001 and the price was around 80p per litre. Now it is close to £1 a litre and everybody is upset with this 25% hike in 5 years.
Here in South Africa, the price of fuel increases every month. In the past 5 years, it has trebled in price. To add insult, we produce oil and sell it to Botswana, where it is half the price. It has even become costly to run a cheap 1.3L car now!
In Zimbabwe, petrol costs around £2 a litre and people can't even get supplies!
Matthew Dean, Pinetown, South Africa
Here in Canada we crossed the $1 per litre barrier some months ago. People have very short memories and I cannot (or try not to) remember twelve years ago when I arrived in Canada when I could fill my tank up and still have change from $15 (GBP7.50). Still, the high cost of fuel will drive the development of alternatives.
Stephen Campbell, Maple Ridge, BC, Canada
I've just returned from a business trip to Saudi Arabia where petrol costs just 60 halalahs per litre; that's about 9 pence! If the British government weren't so incompetent in the way they spend public money they'd be able to lower fuel duties and keep prices at manageable levels!
David Scott, Reading, England
Currently paying 104.9p for Super Unleaded (Shell Optimax). Regular Unleaded is 98.9 at my local but have seen 94.9 in Bracknell last weekend.
Calum Ferguson, Abingdon, Oxon
Tesco have certainly piled up the price. 98.9p for unleaded in Lichfield compared to 96.9p at others. Looking round they were always amongst the cheapest in an area but since there "5p a litre off if you spend £50 offer" they seem to have pushed up the price to compensate (or am I just cynical!) It pays to shop around.
D. Wright, Midlands
In our area of North Hampshire, We've been paying £1 per litre for several weeks now, well before the Israeli attacks started. Oil companies will always use any excuse to increase prices and therefore increase profits. It's one of the many prices we pay for living in a "free" economy!
Mark Coleman, Hampshire
Texaco round here is charging 99.9 for diesel, and has been several times this year. Small rural garages are anything up to 110 for diesel.
We broke the £1 a litre a long time ago.
A few days ago petrol was 91.9p now it's shot up to 95.9p and in other areas petrol is costing 99.9p.