Ministers removed Portugal from the travel “green list” amid increasing worries that coronavirus variants could scupper domestic reopening, with studies indicating the type now dominant in the UK is almost twice as likely to cause serious illness as the one it replaced. The removal of Portugal – the only mainstream tourist destination to which Britons could travel without quarantining on return – and the lack of any new green list countries provoked fury and plunging share prices within the travel industry, and warnings of job losses. Portugal, including Madeira and the Azores, will be moved to the amber list on Tuesday. Seven more countries will be added to the red list, to which virtually all travel is effectively prohibited. Grant Shapps, the transport secretary, said that as well as rising Covid test positivity rates in Portugal, what he called a “difficult decision” hinged on worries about variants, particularly a possible additional mutation of the Delta variant. Data from Public Health England released on Thursday evening has shown that the Delta variant, first detected in India, is dominant in the UK, now accounting for 75% of cases. It also indicated that the Delta variant appears significantly more likely to cause serious illness than the Alpha variant of Covid, which has been dominant across the UK since being first detected in Kent in the autumn. While the PHE team stressed more research was needed, an analysis of 38,805 sequenced cases in England showed that Delta variant had 1.67 time more change of patients needing emergency care or hospitalisation within 14 days than the Alpha, once demographic factors and vaccination status were taken into account. Data from Scotland pointing to a more than twofold higher risk of hospitalisation for those infected with the Delta variant compared with the Alpha. Shapps tied the decision over Portugal to fears that returning travellers could bring in more variants, further jeopardising the government’s timetable to end many remaining Covid restrictions on 21 June. There is still no decision as to whether the planned reopening will happen then, or if restrictions might need to be extended so more people can be vaccinated. A decision is due by 14 June. “We just don’t know the potential for that to be a vaccine-defeating mutation, and we don’t want to take the risk as we come up to 21 June and the review of the fourth stage of the unlock,” he said in a TV interview. Shapps highlighted what he called “a sort of Nepal mutation”. A mutation of the Delta variant, this is suspected of potentially being more resistant to vaccines, but is not under observation by PHE. It has been seen in numerous countries, but only once in Nepal. which carries out very little genome sequencing for Covid. As news leaked out about the green list decision, hours before the official announcement, it wiped hundreds of millions of pounds off the value of tour operators and airlines, and prompted significant anger. Green-list destinations are in effect the only choice for holidays. They allow travellers to return to England without quarantining, although passengers must take a Covid test before coming back and another within two days of arriving. Aside from Portugal, Gibraltar and Israel, the initial 12-destination green list mainly comprised countries into which UK travellers are not allowed, such as Australia and New Zealand, or places like the Falkland Islands and Iceland. Ahead of the three-weekly review of the list, there had been expectation that more tourism centres could be added, for example Spain’s Balearic islands, or some Greek islands. EasyJet chief executive Johan Lundgren said the government had “torn up its own rule book and ignored the science, throwing peoples’ plans into chaos, with virtually no notice or alternative options for travel from the UK”. He added: “This decision essentially cuts the UK off from the rest of the world.” John Holland-Kaye, chief executive of Heathrow airport, said: “Ministers spent last month hailing the restart of international travel, only to close it down three weeks later all but guaranteeing another lost summer for the travel sector.” Henry Smith, the Conservative MP whose Crawley constituency includes Gatwick, said he was “very concerned that we’re not being more ambitious” over travel. “I think we should be going in the other direction and liberalising the amount of countries on the green travel list. “This decision really puts a question mark over a significant number of travel and aviation sector jobs going forward, if they can’t manage to have something of a summer season, I think it’s going to lead to increased unemployment. “As an island trading nation, I think it impacts our economy more broadly, beyond the immediate aviation and travel sectors, and will mean that there will be people in the industry, and beyond, having to come to the government for bailouts and benefits in the coming months.” The bulk of countries remain on the amber list. While it is not illegal to go to one of these for a holiday, it is strongly discouraged. People who come to the UK from an amber-list country must take a Covid test before travelling, and on days two and eight once they are in the UK, and must quarantine at home or in a hotel for 10 days. Anyone returning from the 50 red list countries has to undergo the same testing and self-isolation regime, but to do so while staying in one of the designated quarantine hotels at a cost of £1,750 per adult.