The group, which represents UK-registered airlines, said more countries would be included on the green list if a truly “risk-based” system was used.

Rob Griggs, Airlines UK’s director of policy and public affairs, told the Travel Technology Initiative (TTI) webinar: “The government is very risk-averse on travel. The evidence says there’s no zero risk to opening any part of the economy – whether that’s pubs or schools.

“We can put in measures that create a balanced risk to reopening international travel. If we had a risk-based traffic light system, we would have more countries on the green list than we do now.”

Griggs said Airlines UK was “seeking and pushing for further transparency” on how the government assesses countries within the traffic light system.

“A risk-based traffic light system would let us get going again,” he added. “We’re essentially a closed industry given the nature of the green list at the moment.

“Green should mean green, while amber is higher risk with mitigation through testing or some form or quarantine. Amber should not mean don’t travel.

“The number of countries on the green list was disappointing, and the circumstances around Portugal doubly so.”

Griggs also called for a green watchlist to be placed on countries in the amber list that were on track to move to the green quarantine-free category.

“That would show us countries in amber going in the right direction and would give time to enable carriers to have some lead time,” he added.

Griggs said the UK government seemed to put international travel in a “different category” from other sectors of the economy.

“For travel, it’s seen as almost frivolous and something that people can go without for a few months compared to other things,” he added.