A planned strike at Scotland’s only oil refinery threatens to disrupt fuel supplies and lead to flight delays.
A Treasury report warned that even a two-day strike could lead to power cuts and Grangemouth owners Ineos said that to safely close the refinery and reopen it would take three weeks, report the Sunday Times.
The Treasury also warned that there could be an impact on long-haul flights and petrol supplies.
Workers at the Ineos site have already started an overtime ban and work to rule.
Unite members have voted for the industrial action in support of Unite convener Stevie Deans.
He was suspended, then reinstated, by Ineos over allegations linked to his involvement in the row over the selection of a Labour candidate in Falkirk, where he is chairman of the local constituency party.
He faces an investigation by Ineos over issues linked to the Falkirk row.
Unite have accused Ineos of trying to "provoke" a strike, which it warned would be "hugely damaging" to the UK economy.
A previous three-day stoppage at the site in 2008 was said to have cost hundreds of millions of pounds in lost production and other knock-on effects.
