Passengers arriving into the UK are being warned they may experience delays as staff at passport control go on strike.
The Public and Commercial Services union has called a 24-hour strike, which will affect Border Agency staff in the UK.
Passport control staff will be joined by teachers and civil servants on the walk-out, with protests planned in cities across the UK.
The dispute is over the government’s plans to cut pensions for public sector staff.
Low cost carrier Ryanair has called on the government to keep passport checks at UK airports open by drafting in army and police officers.
Ryanair’s Stephen McNamara said: “With traffic and travel paramount to passengers, especially families, at this time of year there can be no excuse for strikes which are clearly designed to bring misery to the travelling public.
“The Govt should call in the army or police to prevent delays for passengers who have already had passports checked before boarding aircraft destined for the UK.”