Summer holiday plans have received a major boost after Boris Johnson blocked the creation of a controversial new "amber watchlist" for foreign countries.

The extra category in the Government’s travel traffic light system would have left popular holiday destinations under threat of imminently turning red, forcing travellers into hotel quarantine on their return even if fully vaccinated. 

Mr Johnson’s decision – which came as he pledged to keep travel rules "as simple as possible" – allows millions of people planning to get away to Europe to avoid new complications.

Spain, Greece and France had been rumoured to have faced being added to the watchlist, but now travellers heading to those destinations can now do so without the threat of being recategorised as red hanging over them.

However, on Monday night there were fresh calls from senior Tory MPs and industry leaders for Mr Johnson to go further and ditch the green-amber-red system entirely, replacing it with a single red list.

Travel countries on the red, green and amber list

It comes as 21,952 new Covid cases were registered in the UK – the lowest figure in almost five weeks – meaning that, a fortnight after the final step of reopening in England, the number of daily cases is still falling.

Asked about the travel rules on Monday, Mr Johnson said: "I understand how much people plan, prepare, for the summer holidays. But we have also got to remember this is still a dangerous virus and we must try to stop variants coming in, must stop importing variants from abroad, so we have to have a balanced approach.

"What I want to see is something that is as simple and as user-friendly for people as possible."

Under the current rules, foreign countries are divided into green, amber or red categories. Travellers returning from green countries do not have to quarantine but must take a Covid test on return.

The same is true for double-jabbed travellers returning from amber countries, but for red countries all travellers must quarantine for 10 days in government-selected hotels at a cost of £1,750 for an adult.

Last week, ministers signed off plans to create an "amber watchlist" for countries at risk of imminently turning red – but the plans triggered a backlash from Tory MPs and the travel industry, with warnings that holiday plans for countries on the list would be cancelled, with travellers unwilling to take the risk.

A Downing Street source said Mr Johnson’s intervention on Monday could be taken as confirmation that he had scrapped plans for a watchlist.

The decision came after Tory MPs bombarded Grant Shapps, the Transport Secretary, and other ministers involved with calls and messages making their disquiet clear. One who talked to Mr Shapps told The Telegraph of the rules before the about-turn: "This is genuinely vote-losing stuff. People are genuinely p—– off with this."

More key decisions on travel will be made this week after Britain reopened to the world on Monday by allowing fully vaccinated travellers from the US and EU to visit without quarantining. 

New green, amber and red lists will be announced – expected to come on Thursday, though that date has yet to be set in stone – after ministers have looked at the latest Covid data.

France is expected to be removed from the "amber plus" list, a recently created category requiring all travellers, even if double-jabbed, to quarantine upon returning home.

Its inclusion sparked a furious reaction in Paris following claims the decision was based on levels of the beta variant on the island of La Reunion rather than in mainland France.  

Jean-Baptiste Djebbari, the French transport minister, said the decision was based on questionable science and urged Mr Johnson to reverse course.Clement Beaune, the country’s junior minister for EU affairs, said the restrictions were "a little bit political" and discriminatory.

Government sources stressed that the "amber plus" list and the green watchlist – the latter for countries that could imminently turn amber – could remain.

Pressure is growing for the traffic light system to be replaced with something much simpler, such as the rules used in America. The organisers behind Save our Summer, a campaign group backed by 900 travel businesses, wrote to Mr Johnson backing such a change.

"This enables fully jabbed US citizens to travel to countries that will allow them through their borders, take one pre-departure test on their return and then not have to quarantine when they get back to the US," said the letter.

"There would continue to be some red countries which would be out of bounds, but the majority of destinations would be accessible to the fully jabbed. This easy-to-understand policy would help the UK travel sector to recover, build confidence quickly among consumers and still protect our country’s health needs with pre-departure testing."

Stephen Hammond, a former transport minister and Tory chairman of the parliamentary group for business travel, said the traffic light system should be replaced with a "clearer" approach under which the fully jabbed could travel abroad freely.

He said the "inconsistencies" in the system had undermined confidence in travel, adding: "My personal view is that I am not quite sure what is the difference between green and amber.

"The graded traffic light system has probably done its time, and I would go for a clearer system. We are moving to a point where we are recognising almost all of the world for travel if you are double vaccinated. Freedom to move around ought to be more important."

Simon Jupp, a member of the transport select committee, backed an overhaul that would abolish amber to create a system based simply on green or red countries.

“The rules must be simplified to build confidence in the travel industry and amongst passengers. More uncertainty will plunge morale even further and put thousands more jobs at risk. Green or Red (no amber) is simpler and sensible,” he said.

Henry Smith, Tory chair of the all party Future of Aviation group, said: “There is a growing backlash against the amber watch list but whether that’s enough for it to be ditched is the $64,000 question. There is growing pressure against the concept.”

He called for overhaul of traffic light system to simplify it with an expanded green list, and mandatory PCR tests replaced with cheaper lateral flow tests. He said he had “sympathy” with calls to scrap the traffic lights because it had become “overly bureaucratic and therefore compromised.”

“It might be the simplest thing to do is overhaul it altogether,” he added. It came as travellers at Heathrow faced long queues over the weekend after an estimated 80 out of 300 Border Force officials were absent owing to Covid, with dozens of others having to self-isolate. That led to queues reportedly a quarter of a mile long at one point, with holidaymakers facing delays of more than an hour.

In a tweet, Heathrow Airport said: "Waiting times at the border have on occasion been unacceptable and we have called on the UK Government to address the problem as a matter of urgency."

The delays have been worsened by problems with the airport’s e-passport gates, which have a higher than normal rejection rate because of the introduction of passenger locator forms to the technology.

On Monday night, it emerged that the head of the Joint Biosecurity Centre, which advises the Government on travel rules, resigned from the post earlier in the summer and is yet to be replaced.  

Labour said it was "reckless" that the post had yet to be filled following the departure of Clare Gardiner. Sources said recruitment for the job was at an advanced stage.