Legal action against the UK government’s COVID-19 travel curbs is gaining momentum with the country’s biggest tour operator, TUI Group and a number of airlines joining a challenge lead by Ryanair and the Manchester Airports Group (MAG).

The legal bid - backed by easyJet, British Airways' owner IAG International Airlines Group, and Virgin Atlantic - is an attempt to get the government to be more transparent in how it determines which countries are on the green, amber, and red lists under the UK’s “traffic light” system for international travel. The system ranks countries according to their COVID-19 risk and accordingly imposes quarantine measures on travellers on their return to the UK.

The result has been that the UK travel industry remains effectively closed as rules require 10 days quarantine for arrivals from all European Union countries and the United States, which are on the amber list. The UK government still advises against travel to most countries, except for a handful that are on the green list.

The judicial review has been prompted by the lack of transparency in how the government made decisions in its first review of the traffic light lists on June 3, which saw Portugal unexpectedly and without prior notice moved from green to amber, causing chaos for holidaymakers and the industry alike. The government has also delayed the final lifting of lockdown for a further month to July 19.

During a “Travel Day of Action” lead by the Association of British Travel Agents (ABTA), pilots, cabin crew, travel agents, and other travel industry workers on Wednesday (June 23) protested and picketed across the UK, urging politicians to reopen foreign routes. The protests were timed ahead of the government’s second review of requirements for international travel at the end of June.

In court papers - in which both the Secretary of State for Health and the Secretary of State for Transport are named as the defendants - MAG said the government had a duty to clearly explain how it makes decisions on categorising countries, and to publish the supporting data, given the “dramatic” impact these decisions have on aviation businesses.

A spokesman for MAG told reporters the court had accepted its application for an expedited hearing and the Transport Minister and the Health Minister had until Monday (June 28) to file a defence. A date for a hearing was likely to be set either later next week or for the following week, added the spokesperson.

The government has stated its travel rules sought to balance the reopening of international travel with safeguarding public health and protecting the country’s vaccine programme.

But Ryanair has charged the UK travel policy was “a confusing go-stop-go-stop system, which is doing untold damage to the UK’s inbound tourism industry”.

“The UK’s COVID travel policy is a shambles,” charged Ryanair chief executive Michael O’Leary. “The green list is non-existent because countries such as Malta and Portugal, with lower COVID case numbers than the UK and rapidly rising vaccination rates, remain on amber. Meanwhile, UK citizens almost 80% of whom will be vaccinated by the end of June, continue to face COVID restrictions on travel to and from the European Union, despite the fact that the majority of the European Union citizens will also be vaccinated by the end of June.”

MAG chief executive, Charlie Cornish, said: “The government is not being open and we simply cannot understand how it is making decisions that are fundamental to our ability to plan, and to giving customers the confidence to book travel ahead.”

“When this framework was put together, consumers were promised a waiting list to allow them to plan," commented easyJet chief executive Johan Lundgren. "Yet the government has torn up its own rule book and ignored the science, throwing peoples’ plans into chaos, with virtually no notice or alternative options for travel from the UK. This decision essentially cuts the UK off from the rest of the world.”