A key North Sea oil pipeline is expected to be shut down later on Saturday, because of a planned strike at the Grangemouth refinery.
BP is to shut the Forties pipeline, which brings ashore a third of the UK's daily crude oil output, in response to the stoppage, set to start on Sunday.
Production at the refinery has already halted ahead of the strike.
The authorities say there is enough fuel to go round, but some garages in Scotland are already running out.
