"The latest changes have shattered the fledgling confidence in air travel including for Christmas and new year bookings," said BALPA in a statement.

Britain, which has so far reported 11 cases of the variant, has said arrivals from all countries would have to self-isolate until they receive a negative result from a PCR test and that face masks must be worn in retail settings.

The government has also added about 10 African countries to the red list over the last few days after Omicron was first detected in South Africa.

BALPA also asked the government to enforce restrictions based only on sufficient data.

"We call again on government to act with the data and to support a vital UK industry. This includes government funding the expensive PCR tests and actually sequencing traveller's tests so we can have an effective and data driven policy," BALPA said.

(Reporting by Aby Jose Koilparambil in Bengaluru; Editing by Shailesh Kuber)