A pedestrian walks past the closed gates outside Victoria Underground Station London, on August 19, 2022, as strike action on Buses, National Rail and London Underground affects services. AFP
Wages this year have failed to keep pace with rocketing consumer prices, sparking a cost-of-living crisis that has resulted in mass UK strike action across multiple sectors.
British inflation surged in October to a 41-year peak at 11.1 percent on soaring energy and food bills.
Heathrow is "braced for major disruption" as baggage handlers employed by contracting firm Menzies started their strike, trade union Unite said.
The walkout "will lead to disruption, delays and cancellation for flights leaving Heathrow Terminals 2, 3 and 4" by airlines including American Airlines, Air Canada, Lufthansa and Swiss Air, it added.
"Menzies is a wealthy company and it can fully afford to pay its workers a decent pay increase," said Unite boss Sharon Graham.
A Heathrow spokesman insisted no cancellations were anticipated, adding it would seek to minimise the impact.
In a separate development, the Communication Workers Union said postal workers had voted overwhelmingly for more strikes this year and next, affecting deliveries in the run-up to Christmas and opening hours at post offices.
The CWU said those in charge of Royal Mail, which employs delivery workers, "need to wake up and realise we won't allow them to destroy the livelihoods of... workers".
Formerly state-owned Royal Mail recently announced it would axe up to 10,000 jobs, blaming the move partly on staff strikes that contributed to a first-half loss.
Post offices themselves are owned by the government.
Britain has seen strikes this year in various sectors, spearheaded by railway staff. State-employed lawyers have also walked out while nurses and teachers are considering action.
In the private sector, plush London department store Harrods faces the threat of a strike by security guards over the busy festive period.