Just 12 countries and territories made the so-called "green list". They include Portugal, Israel, New Zealand, Australia and the tiny Faroe Islands.

The top four destinations - Spain, France, Italy and the United States - were among those left off, angering stricken airlines and holiday companies battling for survival. Those four sit in the amber category, requiring self-isolation for those returning to the UK.

Turkey, another big holiday destination, was added to a red list. Thatrequires travellers to spend 10 days in managed hotel quarantineon their return, which they must pay for themselves.

While a legal ban on all non-essential international travel will be lifted for the first time since January, the government said people should still avoid travelling to countries on the amber or red lists for leisure.

"Today marks the first step in our cautious return to international travel, with measures designed above all else to protect public health and ensure we don’t throw away the hard-fought gains we’ve all strived to earn this year," transport minister Grant Shapps said.

Airlines, holiday companies and tourist hotspots in southern Europe have been waiting for big-spending Britons to start travelling again, but they will have to wait a few months longer for a full rebound to take off.

With Portugal as the first major Mediterranean holiday destination to make the green list, Thomas Cook and Club Med said bookings there were already up 250% on last Friday. TUI said it had added more flights to Portugal.

The list will be reviewed every three weeks. It applies only to people from England for now, but devolved administrations in Scotland, Wales and Northern Ireland are expected to accept it too.

Those travelling to countries on the green list will have to take two COVID-19 tests, one before arrival back into the UK and one within two days of returning.

'EXCESS OF CAUTION'

Trade bodies for pilots and airlines, airports and holiday groups said Britain was being excessively cautious and such a limited reopening would continue to drag on an industry that had taken great strides to manage safe travel.

Experts have also said prices could shoot up for bookings to the few places on the green list. Shapps said airports could also see longer delays as COVID-19 test results must be checked.

Many destination countries also have their own requirements, with many still effectively closed.

"This excess of caution from the government is extremely disappointing for everyone who works in the travel sector," Brian Strutton of the British Airline Pilots Association said.

The travel industry had argued that Britain's rapid vaccination programme should enable it to open up more quickly. But the government has prioritised efforts to prevent coronavirus variants from entering the country.

Heathrow Airport, the country's biggest, and British Airways (ICAG.L) both urged the government to add more countries to the green list when it next reviews travel in early June, and to let those who have been fully vaccinated travel without restrictions.

"The government should help people plan ahead by publishing a list of countries expected to be on the green list for the summer holidays so that passengers are not faced with high prices for last-minute bookings," Heathrow CEO John Holland-Kaye said.

Before the announcement, the head of British Airways-owner IAG had also called on the UK and the United States to open a travel corridor, given their high vaccination rates.

($1 = 0.7208 pounds)