By Sachin Ravikumar and Farouq Suleiman

LONDON (Reuters) – British Airways staff at London’s Heathrow airport voted on Thursday to strike over pay, threatening disruption at one of Europe’s busiest aviation hubs during an already chaotic summer for air travellers.

Air passengers across Europe have already faced lengthy delays and cancellations of hundreds of flights in recent weeks as airports struggle to cope with a shortage of trained staff and strong post-pandemic demand.

Any strike at Heathrow is likely to add to the pressure.

The proposed industrial action relates to less than half of the airline’s Heathrow-based check-in and ground staff in largely customer-facing roles, including assisting passengers and handling baggage.

The GMB union said 95% of BA staff at Heathrow airport who voted backed strike action after BA failed to roll back a 10% pay cut imposed during the pandemic. Around 700 workers had been balloted, of whom 80% voted.

The strike would likely take place during the peak summer holiday period over the next two months, GMB said, warning Heathrow would likely face a “summer of strikes”. Workers must give two weeks’ notice to BA before carrying out any strike.

The news also comes in a week when much of Britain’s rail network is crippled by industrial action as union bosses and train operators face off over demands that workers’ pay increases to keep pace with surging inflation.

“We’re extremely disappointed with the result,” British Airways, owned by International Consolidated Airlines Group (IAG), said in an emailed statement.

“Despite the extremely challenging environment … we made an offer of a 10% payment which was accepted by the majority of other colleagues. We are fully committed to work together to find a solution.”

Prime Minister Boris Johnson’s spokesman said British Airways should make contingency plans to minimise disruption.

GMB said British Airways’ senior management had had their pre-pandemic salaries reinstated while ground staff hadn’t. IAG Chief Executive Luis Gallego received total pay of 1.1 million pounds ($1.4 million) in 2021, the company’s most recent annual report showed.

“BA have tried to offer our members crumbs from the table in the form of a 10% one-off bonus payment, but this doesn’t cut the mustard,” GMB National Officer Nadine Houghton said in a statement.

A Heathrow spokesperson said the airport would “support British Airways to minimise any potential disruption to passengers.”

Demand for air travel has been stronger than expected as Heathrow separately on Thursday raised its forecast for passenger numbers this year to 54.4 million from 53 million previously.

($1 = 0.8150 pounds)

(Reporting by Sachin Ravikumar, Farouq Suleiman and Muvija M; editing by William James and Susan Fenton)