Hundreds of airport workers will go on strike at Heathrow the day before England's first World Cup match.
Unite said around 700 of its members working in ground handling and cargo, for companies that operate out of Heathrow, will take industrial action for three days from November 18.
The union said airlines affected will include Qatar Airways which has scheduled extra flights during the World Cup.
England's first match is against Iran on November 21, meaning fans could get swept up in the chaos.
The strikes will come as thousands of England and Wales fans will be heading to the Middle East to watch the tournament.
Unite general secretary Sharon Graham said as part of statement: "Our members at Dnata and Menzies undertake highly challenging roles and are simply seeking a decent pay rise."
She added that "both companies are highly profitable and can fully afford to make a fair pay increase", and that "the workers at Heathrow will have Unite's complete support during this dispute".
When the prospect of the strike was first tabled last month, Unite regional officer Kevin Hall said: "Strike action will inevitably cause severe disruption and delays across Heathrow, especially for football supporters travelling to the World Cup.
Unite said pay offers from the two companies range from 2% to 6%.
With inflation running at above 12 per cent in the UK, both offers represent a significant pay cut.
A Heathrow spokesperson said: "We are aware of proposed industrial action from Dnata and Menzies colleagues at Heathrow, and we are in discussions with our airline partners on what contingency plans they can implement to support their ground handling should the strike go ahead.
"Our priority is to ensure passengers are not disrupted by airline ground handler shortages."
Ground handling is an airline responsibility and each airline has its own arrangements for providing these services.
Brits are expected to make up a major part of the travel fan force heading for Qatar this winter.
U.S. tourists make up 26 per cent of such visitors, with Canadians second at 10 per cent and Britons third at nine per cent.
Last month a spokesperson for dnata ltd UK said: ““It is disappointing that Unite plans to progress with this costly industrial action, despite our offer to staff of an award which, with previous increases, amounts to a pay rise of 15.5% (20.2% for HGV drivers) since December 2021. This is in line with inflation and amongst the best in the industry.
Alex Doisneau, Managing Directo at dnata UK, said: “We would like to reassure our customers, partners and passengers that we are implementing contingency plans to minimise disruption to our operations.
“The union’s proposition is unrealistic and doesn’t reflect the challenging economic environment we find ourselves in as a business. Despite our sustained commitment to the UK and its communities, the impact of the pandemic, rapid inflation and other local market conditions mean that our UK Airport Operations business is now making a financial loss each month.
"The increase in salary suggested by Unite is irresponsible and would undoubtedly impact our business’ ability to operate in the best interest of our workforce in the long term.
“Our offer has been overwhelmingly accepted by other staff at the airport and we remain committed to reaching a meaningful and mutually acceptable agreement for all parties.”
A spokesperson for Menzies said: “Unite are being incredibly obstructive by refusing to join discussions regarding a pay increase for our Heathrow ground handling workforce. We urge Unite to take part in these negotiations, alongside the other trade union, and to continue separate discussions with our Heathrow cargo operations.
"This threatening of industrial action is all about creating sensationalist headlines rather than doing what’s right for their members. Strike action will benefit no-one and will only delay the process at a time when our employees need the increase now.
"We are ready and willing to continue pay discussions, which we believe is in the best interest of our employees. I also want to reassure our airline customers and their passengers that we have robust contingency plans in place should Unite elect to continue with unnecessary industrial action.”
