Heathrow Airport reopened its Terminal 3 site for the first time in more than a year as the processing base for arrivals from red list countries after complaints arose of long wait times and passengers from high-risk Covid-19 countries mixing with others.
The red list currently consists of 43 nations from which arrivals are deemed to present a high risk of importing coronavirus.
Red list countries from where direct flights to the UK are permitted include India, the Philippines, Pakistan, Kenya and Bangladesh.
Although red list arrivals have to quarantine in an airport hotel for 10 days after they touch down in the UK, the airport terminal mixing meant they came into contact with arrivals from low risk countries such as Portugal, who are then free to mingle in society as soon as they land.
Last month photos showed crowds of arrivals inside the airport arrivals area with little social distancing for hours at a time.
Passengers travelling to the UK on non-direct flights from red list locations however will continue to transit through the airport alongside those from green and amber countries.
The airport blamed the queues and subsequent lack of social distancing between high and low risk arrivals on the time it was taking Border Force staff to process people arriving back into the UK.
The decision to separate arrivals on direct flights from red list destinations was welcomed by the GMB union, which had previously warned that “bottlenecks” are putting passengers and staff at risk.
Heathrow insisted there were “several layers of protection to keep passengers and colleagues safe”, such as mandatory testing for all arrivals, segregation and ventilation.
An airport executive said in April that passengers are being forced to queue for up to six hours to be processed through immigration halls.
Heathrow shuttered Terminal 3 in April last year to save costs after the Covid-19 pandemic forced global travel numbers to collapse.
Transport secretary Grant Shapps is due to update the list of destinations under the Government’s traffic light travel system on 7 June.