Britain said on Monday it was too soon to say whether or not international summer holidays could go ahead this year, suggesting a planned reopening of outbound travel could be pushed back beyond May 17.

Britons are among the highest spending tourists in Europe so the fortunes of the continent’s summer season and the desperate travel industry will depend on when tourists can return to the beaches, cafes and tavernas of southern Europe.

Britain plans to use a traffic-light risk system for countries once non-essential international travel resumes but the government said it was too soon to say which countries could be given the green light that would only require testing before and after travel.

“Taking into account the latest situation with variants and the evidence about the efficacy of vaccines against them, we will confirm in advance whether non-essential international travel can resume on 17 May, or whether we will need to wait longer before lifting the outbound travel restriction,” a government review said.

British media suggested countries on the green list, requiring only testing before and after travel, could include Portugal, Malta, Israel, the United Arab Emirates and the United States.

Under the original plan, international travel would not resume until May 17 at the earliest. 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.

British Prime Minister Boris 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 programme rolling out rapidly across the UK and infection numbers falling, Johnson said England could proceed to Stage 2 of his roadmap out of lockdown from April 12.

He said people should continue to work from home where they can and minimise domestic travel. He also confirmed that the government was looking at a COVID-status certification system, or vaccine passport, to help reopen larger events.