BP tanker drivers have begun a three-day strike at Petroineos's Grangemouth refinery in Scotland over a plan to transfer some of them to another employer, which would affect their pensions and pay.
Some 42 members of the Unite union are striking over Air BP's decision to award a contract to express delivery company DHL to take over the transport of fuel to Scottish airports such as Edinburgh, Glasgow and Aberdeen.
The switch will entail the transfer of 15 BP employees on an aviation distribution contract to DHL in March, a BP spokesman said.
The strike began at 0400 GMT on Friday and will go on until 0800 GMT on Monday, Unite said.
"Two thirds of the workforce affected stand to lose up to GBP£1,500 (USD$2,300) a year on their salary because they're losing a share-match scheme that BP introduced last year as opposed to a pay rise," a Unite spokesman said in an interview by phone from the picket line.
He added that one third of the staff on the aviation contract will lose up to GBP£13,000 a year per person from their pensions.
"The dispute has been rumbling on since last year, when BP offered the share-match scheme instead of a percentage pay rise," he said.
BP said that contingency plans had been put in place to try to minimise disruption to fuel deliveries.
"We've been sending deliveries using other drivers to ensure there is continuity of supply to airports and retail forecourts," the BP spokesman said. "We believe stocks are at a good level."