Mark Serwotka, general secretary of the Public and Commercial Services (PCS) union, predicted there would be a “massive escalation” in union action within the civil service in January unless ministers enter into negotiations.
About 1,000 PCS members employed by the Interior Ministry to operate passport booths walked out the door at 8 p.m. Friday Heathrowthe airports of Birmingham, Cardiff, Gatwick, Glasgow and Manchester, as well as the port of Newhaven in East Sussex.
The Border Force strikes take place every day for the rest of the year except December 27.
Mr Serwotka said he hoped the government “will do the right thing and come around the negotiating table and put some money forward”.
He told BBC Radio 4’s Today programme: “We are raising money, we have a strike fund that means we can support this action.
“Our strike mandate lasts until May. We will support this action until May and we would vote again if we had to.
“I think in January you will see a huge escalation of this action in the civil service and the rest of our economy unless the government comes around the negotiating table.”
On Friday, about 250,000 passengers with flights will arrive at the affected airports.
Travelers were warned by Border Force bosses to expect delays amid fears that long queues at passport control could lead to people being held on planes, disrupting later departures.
But the deployment of military personnel to check passports ensured that passengers did not appear to be delayed on the first day of the strikes.
A Heathrow spokeswoman said: “The morning rush hour has started well.
“Immigration halls are free flowing at Heathrow, with Border Force and the military contingency providing a good service.”
A Gatwick spokesperson told the PA news agency: “Everything is going well at the moment.
‘There is enough staff. The e-gates all work. It goes well.
“As far as we know there are no delays and no queues at the moment.
“I’m in the arrivals hall and the passengers are flowing normally.”
Aislinn Laing, co-bureau chief of Reuters international news agency in Spain, wrote on Twitter shortly before 10am: “Just flew into Gatwick from Madrid.
“Military manned frontier, absolutely no queues, faster than usual and service from a naval officer with a beaming smile.
“I braced myself to feel a little embarrassed about the state my country is in, but felt very proud instead.”
A passenger with the Twitter username @olicohen wrote: “Got through border control at Heathrow airport in the fastest time in 10 years.
“Be guided with military precision.
“If only the military could control it permanently.”
Defense Secretary Ben Wallace announced that members of the armed forces will receive an additional £20 for each day they train or deploy to cover union action over the festive period.
More than 1,000 naval, army and RAF personnel have been trained in tasks such as passport control and ambulance driving in recent weeks.
Meanwhile, mail delivery and driving lessons will be disrupted by strikes in the days leading up to Christmas.
Employees of Royal Mail, National Highways and Driver and Vehicle Standards Agency (DVSA) are taking industrial action on Friday.
They will continue their strike until Saturday, when workers represented by the Rail, Maritime and Transport (RMT) union, Abellio London bus workers and Environment Agency staff launch separate waves of action.
This follows two days of strikes by NHS staff, with thousands of nurses walking out on Tuesday and ambulance crews at the picket lines on Wednesday.
Prime Minister Rishi Sunak said he is “sad and disappointed at the disruption being caused to so many people’s lives, especially at Christmas time”.
He continued: “When it comes to the difficult issue of setting government pay, the government has acted fairly and fairly in accepting all the recommendations of the public sector wage control agencies.”
National Highways workers responsible for motorways and major A roads in London and the South East, also represented by the PCS, will continue their four-day strike which began on Thursday.
Postmen represented by the Communication Workers Union walked out from their action on the fifth day of December in a move that Royal Mail criticized as “a cynical attempt to ransom Christmas”.
The company said it will do everything it can to deliver Christmas mail, saying the union action has cost it £100 million.
RMT rail workers will strike again from 6pm on Christmas Eve, potentially preventing people from coming home for Christmas.