Bookings for holidays to Portugal have gone "through the roof" after the country was added to the government’s green travel list, Thomas Cook has said.
The European nation is one of just 12 destinations where travellers can visit from 17 May without needing to self-isolate upon their return to England.
On Friday night, Thomas Cook said it had taken more bookings for trips to Portugal in a single hour than it did in the whole of April.
Searches for Portugal have increased by 264%, while enquiries about Gibraltar – another destination on the green list – rose by 277%.
The company’s head of PR, David Child, said tourists appeared "poised, ready and waiting to go" when Transport Secretary Grant Shapps unveiled the relaxed rules at a Downing Street briefing.
Despite the surge, he said bookings are lower than what they normally would be at this time of year – and although the price of flights may increase, many hoteliers are "not raising their prices yet" because they are "desperate for custom" and have rooms to fill.
Other destinations on the green list include Israel, Australia, New Zealand, Singapore, Brunei, Iceland and the Faroe Islands, plus several small remote islands that are British Overseas Territories.
However, not all of these areas are accepting arrivals from British tourists – with entry to Australia, New Zealand, Singapore, Brunei and the Faroe Islands severely restricted.
No plans on international travel have been announced in Scotland, Wales and Northern Ireland yet, but these administrations are expected to introduce "broadly similar" measures.
Airlines and holiday companies, many of whom are battling for survival after being hit hard by the coronavirus pandemic, have expressed anger over the green list.
Four of the most popular destinations for British tourists – Spain, France, Italy and the US – were left off the green list altogether. Instead, their amber rating means people who travel to these countries will need to self-isolate on their return.
EasyJet boss Johan Lundgren said: "The decision to put so few European countries into the green tier is simply not justified by the data or the science and is inconsistent with the approach to reopen the domestic economy."
He called on the government to clarify when other European countries are set to join the green list "so that consumers and airlines alike can plan for summer".
The industry body Airlines UK echoed these remarks, and said the government’s plan "represents a reopening of air travel in name only".
Its chief executive, Tim Alderslade, called for "major additions" to the made to the green list when it is next reviewed in three weeks’ time – and warned the UK is "at risk of falling behind and not opening up international travel to key markets".
The pilots’ union Balpa accused the government of an "excess of caution", adding that the new rules will be "extremely disappointing for everyone who works in the travel sector and the millions of people who are desperate to jet away on holiday or business".
General secretary Brian Strutton added: "Tourists are sat gazing at the amber light, revving their engines, desperate to travel safe in the knowledge that their jabs will protect them. The government must flick those amber lights to green as soon as it possibly can."
And British Airways boss Sean Doyle said the UK needs to urgently reopen travel links with other low-risk countries with high vaccination rates, such as the US, "to restart the economy, support devastated industries and reunite loved ones".
During the Downing Street briefing, Mr Shapps had said the government needed to "make absolutely secure" that the countries the UK reconnects with are safe.