UK Border control at Terminal 2 at Heathrow Airport in London. Picture: Neil Hall/Reuters/African News Agency (ANA)

London - It's the peak of the European summer season and more than a million holidaymakers could face a summer of misery due to strikes at Heathrow Airport.

Unions have warned that Britain’s busiest airport could be "shut down" as part of industrial action over a pay dispute.

More than 4 000 workers including security guards, engineers and drivers, will walk out on July 26 and 27 and August 5, 6, 23 and 24.

Workers backed strikes in eight ballots. 

The Unite union said it followed the rejection of an 18-month pay offer amounting to £3,75 (about R65) extra a day for the lowest-paid employee. It predicted the walkout "could potentially shut down the airport." 

A Heathrow spokesman said: "We are disappointed that Unite will be taking strike action. Following this decision, we will be implementing contingency plans that will ensure the airport remains open and operating safely.

"We will be working alongside our airline partners to minimise disruption caused to passengers. We are proud of our record as a good employer and we remain committed to finding a solution. We have proposed a progressive pay package giving at least a 4.6 percent pay rise to over 70 percent of our front line colleagues."

The union claimed there was discontent over pay disparities between workers doing the same job. 

Staff were also upset at the "massive" package earned by Heathrow chief executive John Holland-Kaye, whose basic pay rose from £2.1 million in 2017 to £4.2 million last year.

Unite’s Wayne King said: "There is deepening anger over pay among workers who are essential to the smooth running of Heathrow.

"They are fed up with being expected to accept crumbs while the chief executive pockets an eye-popping 103 per cent rise in his pay package and shareholders are handed dividends of over £2 billion in the last two years alone."

On the first weekend of the summer holidays in the UK last year the airport recorded its busiest ever day with 261 909 passengers, meaning more than a million could be hit by the proposed walkouts this month and next.

Daily Mail