Members of the Public and Commercial Services (PCS) Union are set to strike tomorrow (June 30th) over a dispute with the government over pensions.
Employees including UK Border Agency staff are planning to stay at home – or even take part in picket lines – in protest of the coalition government's plans to make them pay more into their pension and to work for longer.
The strikes are likely to affect those flying into UK travel facilities such as Heathrow Airport, with long queues expected at passport control and customs, BAA warned.
People heading for departing flights should not be impacted upon as they are usually dealt with by security staff hired by BAA.
BAA runs Heathrow Airport, as well as Southampton, Aberdeen, Glasgow and Edinburgh.
A spokeswoman said: "UK Border Agency [is] advising that passengers who can do so may wish to travel on other dates."
Meanwhile, PCS general-secretary Mark Serwotka asserted that "hundreds of thousands" of public and civil servants are expected to strike, with "millions more" to take the same action later in the year.