Closed pumps are seen on the forecourt of a petrol station which has run out of fuel after an outbreak of panic buying in the UK, in Manchester, England, Monday, Sept. 27, 2021. British Prime Minister Boris Johnson is said to be considering whether to call in the army to deliver fuel to petrol stations as pumps ran dry after days of panic buying. ( AP Photo/Jon Super)

LONDON (AP) — Lines of cars formed at British gas stations for a fourth day on Monday, as the government mulled sending in the army to help ease supply disruptions triggered by a shortage of truck drivers.

As unions called for emergency workers to be given priority for fuel supplies, Petrol Retailers Association chairman Brian Madderson said training had been taking place “in the background” for military personnel to drive tankers.

The government said it had “no plans at the moment” to deploy troops, but was making preparations just in case. Government ministers met Monday to discuss the fuel squeeze.

The Petrol Retailers Association, which represents almost 5,500 independent outlets, said Sunday that about two-thirds of its members had run out of fuel, as the truck driver shortage set off rounds of gas panic-buying.

Long lines of vehicles have formed at many gas stations around Britain since Friday, causing spillover traffic jams on busy roads. Tempers have frayed as some drivers waited for hours.

The Conservative government insisted the U.K. had “ample fuel stocks,” and blamed the problems on consumer behavior.

“The only reason we don’t have petrol on the forecourts is that people are buying petrol they don’t need,” said Environment Secretary George Eustice.

Major fuel firms, including BP, Shell and Esso, said in a joint statement that they expected demand for gas to “return to its normal levels in the coming days.”

“We would encourage people to buy fuel as they usually would,” the statement said.

But critics urged the government to get fuel flowing so the shortage does not have damaging spillover effects on health care, police operations and other crucial sectors.

Dr. Chaand Nagpaul at the British Medical Association said health care workers and other essential services staff should be “given priority access to fuel so they can continue their crucial work and guarantee care to patients.”

Christina McAnea, general secretary of the Unison trade union, urged the government to use emergency powers to designate gas stations for key workers.