It is still too early to book foreign summer holidays, the transport secretary has said, despite countries saying they hope to welcome vaccinated British tourists from May.
Grant Shapps said there were “lots of questions” to answer about “how safe it will be in June to travel”.
People in England could be allowed to go on holiday abroad from 17 May at the earliest, according to current plans.
A Greek minister said his country hoped to welcome visitors from mid-May.
Cyprus and Portugal are also among the countries keen to welcome UK visitors.
Under the current rules, foreign travel from the UK is banned apart from for exceptional reasons.
While 17 May has been marked as the date that rule could change – the decision is subject to a review closer to the time.
Asked on BBC Radio 4’s Today programme if it was too early to book a summer holiday, Mr Shapps said: “Yes.”
He added: “We have said it will remain illegal to travel internationally until at least 17 May – that’s an at-the-earliest date.”
Mr Shapps said people should look towards 12 April, when he will publish a global travel taskforce report, and said the government was weighing up not only the “extraordinary” UK vaccination rollout but also other countries’ vaccine programmes.
“So there are lots of questions the answer to which we simply don’t know yet about how safe it will be in June to travel around,” he said.
Wales, Scotland and Northern Ireland have not set a date for the start of international travel.
Once travel is allowed again, the success of the UK vaccination programme is likely to make British holidaymakers attractive to countries looking to rebuild their tourism sectors, which have been badly hit by the pandemic.
Many countries are working on their plans to allow tourists and it is not yet clear if there will be some form of international vaccine passport or certificate.
Cabinet Office minister Michael Gove is leading a UK government review into the issue.
Greece tourism minister Haris Theoharis said his country hoped to welcome foreign tourists from 14 May, during an appearance at a travel trade show.
He said: “Regarding 2021, in Greece we are more than optimistic.”
Visitors will be required to have been vaccinated, had a recent negative Covid-19 test or have coronavirus antibodies, he said.
A pilot reopening of borders is likely to take place next month, he added.