Heathrow Airport has dedicated an entire terminal building to arrivals from nations where coronavirus is a high concern.
Travelers from 43 nations on Britain's red list, including India, Kenya, and Brazil, will use Terminal 3 exclusively.
After a sharp reduction in passenger numbers because of the Covid-19 outbreak, the terminal was shuttered in April 2020 to save money.
People traveling from red-list nations must stay in a hotel quarantine for 11 nights, which may cost up to £1,750 ($2,480) for solitary travelers under the UK's traffic light system.
The decision was made to protect travelers traveling from countries on the amber and green lists from becoming infected while passing through the UK's busiest airport.
Passengers at the London airport had previously complained about congestion after being forced to wait in congested, poorly ventilated immigration halls for up to six hours. They said that the congestion was exacerbated by people from both red and non-red list locations congregating in close proximity.
Only British nationals or those with resident rights are permitted entry into the UK from countries on the red list, and they must present a recent negative Covid-19 test. Arrivals from the United Arab Emirates, Qatar, and Oman must stay in a hotel quarantine.
Heathrow officials asserted that “several levels of protection” were in place to keep passengers and employees safe, including required testing for all arrivals, segregation, and ventilation.
“As countries vaccinate their populations at varying rates, red list routes will likely remain a fixture of UK travel for the foreseeable future,” an airport spokesperson said. “Heathrow is adapting to this longer-term reality.”
Heathrow intends to relocate its new red-list processing center to Terminal 4 "as soon as operationally viable."
The possibility of the red list being enlarged in the coming days is growing.
In the face of Covid-19 variations and escalating global infections, Robert Boyle, former director of strategy at British Airways parent company IAG, questioned why the list had not been enlarged sooner.
In a blog post, he claimed that ailing airlines and travel industries were pressuring UK ministers to allow international vacations.
