People hoping to head abroad for Christmas could be hit by long queues at airports this festive season.
The ISU union - which represents 3,500 Border Force, immigration enforcement and visa officers - is threatening strike action in December.
They are fighting for an 8% pay rise for their members in a bid to keep up with an inflation rate which is currently above 10% and the increasingly acute cost of living crisis.
In a message on the ISU's website, the organisation's General Secretary Mark Gribbin described the offer of a 3% increase as a "profound insult".
In a separate membership update posted on its website, the union said that potential strike action would be focused on "Border ports and on Channel Migrant work", and said that it is "also considering a longer period of industrial action over Christmas and the New Year period".
UK Border Force officers are now balloting to strike across the 140 ports and airports in the UK.
If they do it will likely cause major disruption at large travel hubs like Heathrow and Gatwick Airports, and could lead to much longer waits to get through security.
The issue may be particularly acute at Heathrow, which is already looking to recruit 25,000 new security-cleared staff in a bid to manage the peak travel crowds.
The move could also mean the call-up of police or military personnel to deal with people coming across the Channel to the UK in small boats, according to reports.
Border Force staff walking out of UK airports would be a major blow for the sector after almost three very difficult years.
The situation at the aviation hubs has improved in recent months as more staff are brought on board to deal the the spike in demand post-lockdown.
After many baggage handlers and security personnel left the industry during the Covid pandemic, lengthy queues were a regular feature at UK airports this spring and early summer.
A Home Office spokesperson said: “We work closely with all UK ports and airports to ensure passengers and goods can cross the border as smoothly as possible, and will do so in the event of any industrial action.
“Government have robust plans in place to deploy officers flexibly to support the flow of passengers and goods at the UK border.”
