More misery lies ahead for motorists who could face fuel shortages if workers at Northern Ireland's main supplier goes on strike at the end of the week.
Workers at Grangemouth oil refinery in Scotland plan industrial action on April 27 and 28 in a row over pensions.
Refinery owner Ineos has warned that the two-day stoppage will affect supplies for a month sparking concerns over a UK-wide fuel crisis.
Phil McNulty, trade union Unite's chief negotiator, said that all oil which is supplied to Northern Ireland, Scotland and the north of England comes via Grangemouth.
"Ineos is saying there are only stocks in those areas to last four days, while industry analysts are saying there is enough for 70 days," he said.
Ineos has already begun shutting down the site - which produces nine millions of oil daily - to ensure it is secure during the strike period.
Mr McNulty said that it was impossible to say what effect the walk-out would have on retail prices, but he pointed out the danger of panic buying, which has already begun in Scotland.
Grangemouth produces all types of fuel - from petrol and diesel to home heating oil - and Ineos has accused the union of "rushing" to take industrial action.
The company said the stoppage would also effectively close down a large proportion of North Sea oil production as well as some gas production which goes through Grangemouth.
Chief executive Tom Crotty predicted chaos for the whole of the UK in the wake of the industrial action.
"The union is well aware that a 48-hour strike will cause fuel chaos in Scotland and the north of England for weeks on end," he said.
"This is a huge oil refinery and they know you can't just turn it on and off like a tap.
"A month is our best guess but safety considerations will be at the forefront of everything we do. It is not our wish to suspend production at Grangemouth, but Unite has given us no choice.
"They have deliberately chosen a course of action that is the minimum pain for them, but which will inflict the maximum pain on Scotland and the whole of the UK."
He urged union bosses to continue negotiations and drop the strike plans, which he said is "designed to hold the company to ransom".
But Mr McNulty insisted the proposed changes were "unreasonable" and "unnecessary".
Andrew Howard, a spokesman for the AA public affairs unit, said there was no doubt that action at Grangemouth would be felt across the UK. "We have around a dozen refineries in the UK and if one of those closes for a time, all that can happen is that prices go up," he said.