Immigration staff will stage a one-day strike next week in the bitter dispute over public sector pensions, threatening huge disruption at airports, including Heathrow, which is already being hit by massive delays.
The Immigration Services Union (ISU), which represents 4,500 Border Agency staff, said its members would walk out next Thursday at ports and airports across the UK and abroad.
The union is in dispute with the Government over plans to increase the retirement age for public servants.
It said it believed managers would be used to cover its members during the strike.
The Government is already dealing with complaints about long queues at Heathrow and is planning to draft in 80 extra staff.