Portugal, the Canary Islands, Corfu and Crete are among popular European holiday destinations that have been declared safe for travel by the Foreign Office, raising hopes that they could be on the travel green list.
Within the last week, the Foreign Office has quietly dropped its advice against non-essential foreign travel to Portugal – excluding the Azores – Malta, and the Greek Islands of Rhodes, Kos, Zakynthos, Corfu and Crete, some of the most popular destinations for British tourists.
It has also rated the Canary Islands and Israel, one of the most highly vaccinated nations in the world, safe for travel, stating that it "no longer advises against all but essential travel" to the destinations.
The Foreign Office advice against non-essential travel to mainland Greece and Spain remains, mirroring the policy last year that allowed holidaymakers to visit the islands because their Covid rates were lower than the mainland.
The move comes as the Government prepares to lift its ban on foreign travel from May 17. On Friday it will unveil its green list' of countries to which holidaymakers can fly from the same date without having to quarantine on their return.
The list – expected to be no more than a "tiny handful" of fewer than 10 destinations – is based on countries with high vaccination rates, low prevalence of Covid and its variants and their capacity for genome analysis of the virus.
The Foreign Office advice, thought to be based on infection and vaccination rates, provides an indicator to the Government's thinking on the safety of a country. Unlike the green list, it also takes account of other factors such as the capability of its health system and terrorist risk.
The Department for Transport (DfT) is responsible for publishing the green, amber and red lists of countries which, unlike the Foreign Office list, sets out the restrictions holidaymakers face on their return to the UK.
Industry sources said there was no guarantee that the countries flagged by the Foreign Office will be on the DfT's first green list from May 17 but, if not, it still augured well and particularly for subsequent reviews of which countries are on the list, which will be conducted every three weeks.
The Foreign Office advice also means insurers will cover travel for anyone going to the destinations and that tour operators can fly into them.
"It's basically saying that, on vaccination and Covid rates, the Foreign Office thinks it is a safe country," said a senior industry source. "Operators could not fly there if the Foreign Office didn't change its advice. It paves the way for significant travel to the destinations."
Gibraltar, Malta, Israel and Iceland fit the "green list" criteria, with Portugal and the US as contenders. Australia and New Zealand, with virtually zero Covid infection rates, are also in the frame.
It came as tourist leaders in the Balearic islands said they would welcome British holidaymakers as soon as this month. Rosa Ana Morilla Rodriguez, the director general of tourism for the islands, told Sky News she was "very optimistic" that a deal could be agreed to open the Balearics to British holidaymakers.
She said she was hopeful that the islands – Mallorca, Ibiza, Menorca and Formentera – could be included on the UK's "green list", adding: "We have the right numbers, we have the right measures in place that will allow us to be considered green."
Meanwhile, Professor Neil Ferguson, a senior scientific adviser to the Government, said there was "no risk" to British holidaymakers visiting foreign countries this summer if Covid cases there could be driven down to UK levels.
"I think if for instance, by the summer, infection levels in France and Italy are the same sort of level as they are here, then there's no risk associated with travelling overseas,” said Prof Ferguson, from Imperial College, London, whose modelling work informs government scientists.
"The risk comes from going from a place like the UK with very low infection levels and going to a place with much higher infection levels and therefore having the risk of bringing infection back.
"If the two places are at comparable levels, and that's what the EU is saying, then there is no particular risks associated with travel."
The European Commission has said it will ease restrictions on travel to the bloc amid progressing Covid-19 vaccination campaigns and lower infection rates.