LONDON (Reuters) - British Prime Minister Boris Johnson said on Monday it was too soon to say whether international summer holidays can go ahead this year, a remark suggesting a planned reopening of outbound travel could be pushed back beyond May 17. Britons are among Europe’s highest spending tourists so the fortunes of the continent’s summer season and the travel industry, hit hard by restrictions imposed on travel because of the COVID-19 pandemic, will depend on when tourists can return to the beaches, cafes and tavernas of southern Europe. Asked about summer holidays, Johnson told reporters he did not want the virus to be reimported into the United Kingdom from other countries so it was not possible to give more clarity as the global situation was evolving so fast. “Obviously we are hopeful that we can get going from May 17th, but I do not wish to give hostages to fortune or to underestimate the difficulties that we are seeing in some of the destination countries that people might want to go to,” he said. “I wish I could give you more on that, I know that people watching will want to know exactly what they can do from May 17, but we’re not there yet,” Johnson said. “As soon as we have more solid information, more solid data, we’ll let you know.” A British government review of travel said that it was not yet clear if tourists would have to wait beyond May 17 for the outbound restrictions to be lifted. The lack of clarity from Johnson disappointed Britain’s biggest airport and travel companies which said the sector was teetering on the brink of collapse. “It’s disappointing that the opportunity has been missed to provide more certainty to reunite families separated by travel restrictions, to give sunseekers the confidence to book ahead for their summer getaway,” Heathrow CEO John Holland-Kaye said. “A clearer timeline for the return to international travel is needed,” Holland-Kaye said. Noel Josephides, chairman of travel group Sunvil, told Reuters before Johnson spoke that the industry would need weeks of notice to reopen hotels and resume flight routes. “It is not possible to launch a tour operation with one or two weeks’ notice,” he said. Britain plans to use a traffic-light risk system for countries once non-essential international travel resumes, but the government said it was too early to say which countries could be given the green light that would only require coronavirus tests before and after travel. Countries that could fit on the green list include Portugal, Malta, Israel, the United Arab Emirates and the United States. Countries on the amber list would require self-isolation. Those on the red list would require quarantine. Airlines such as easyJet, Ryanair and British Airways, plus holiday groups such as TUI, hope to avoid a second lost summer but COVID-19 cases have risen in continental Europe. Slideshow ( 3 images ) Johnson said a planned reopening of the economy could take place next week, with the opening of all shops, gyms, hairdressers and outdoor hospitality areas in England. With the vaccine rolling out rapidly across Britain and infection numbers falling, Johnson said England could proceed to Stage 2 of his roadmap out of lockdown from April 12. “I will be going to the pub myself - and cautiously but irreversibly raising a pint of beer to my lips,” Johnson said. Johnson also confirmed that the government was looking at a COVID-19 status certification system, or vaccine passport, to help reopen larger events and to travel. “You’ve got to be very careful in how you handle this and ... don’t start a system that’s discriminatory.”