Passenger figures at Heathrow were down 82 per cent in October when compared to last year, as the Covid-19 pandemic continue to take a toll on global aviation.
The airport also warned data for November was likely to be even worse, as England enters a four-week lockdown.
Long-haul and critical markets for trade suffered the worst declines, Heathrow said.
This was due to the “debilitating quarantine requirements” put in place by the UK government.
Overall cargo volumes were down 23 per cent compared to last year.
Heathrow chief executive, John Holland-Kaye, said: “Aviation is the lifeblood of the UK’s economy, critical for exports of goods and services and imports of vaccines, as well as inbound tourism, students and foreign direct investment.
“Lack of government action is weakening our sector, making it harder for us to support the eventual economic recovery and help deliver the prime minister’s vision of a global Britain.”
Heathrow argued the lack of a testing regime has left British airports unable to compete with EU rivals.
At the same time, the refusal to offer English and Welsh airports business rates relief runs the risk of worsening an already challenging situation and the plans to end VAT-free shopping threatens to kick our industry when its down, a statement added.
The figures come as new research suggests the quarantine regime may be less effective than previously thought.