Ministers are facing a growing revolt on 14-day quarantine plans amid warnings it will 'kill' the travel industry.
The 'blanket' proposals for arrivals to the UK are coming under increasing fire amid claims that are unnecessary and unenforceable.
Aviation chiefs have compared the requirement to hanging up a 'Britiain is closed' sign and suggested the wider easing of lockdown will do little to help restart travel if it comes into force.
Meanwhile, more than 200 businesses have joined a campaign urging the Government to drop the idea.
More Tory MPs have voiced opposition to the regime, unveiled by Priti Patel last month, amid signs of a big rebellion when they come before the Commons later this week.
The system is due to take effect on June 8, with only very limited exemptions such as for lorry drivers. People arriving in or returning to the UK will have to give an address where they are intending to isolate for a fortnight, with the officials carrying out spot checks.
Failure to comply could be punished with £1,000 fines. Transport Secretary Grant Shapps has mooted 'air bridges' to low-infection countries, but as yet there is no sign of that option coming to fruition.
Industry bosses told the Times the quarantine could cost thousands of jobs across the travel, tourism and hospitality industries and hamper the nation's economic recovery.
The government's 'blanket' proposals for arrivals to the UK are coming under increasing fire amid claims that are unnecessary and unenforceable
More Tory MPs have voiced opposition to the regime, unveiled by Priti Patel (pictured) last month, amid signs of a big rebellion when they come before the Commons later this week
Simon McNamara, of the International Air Transport Association (Iata) said: 'If the quarantine is still in place people are not going to travel. It is not a question of being prepared to go through quarantine because they want to travel.
'All the evidence we have is that this will just kill travel. Governments seem to me to have a stark choice.
'They cannot pretend that quarantine enables their international travel markets to open up, because the evidence is quite simply not there.
'If they persist with quarantine it is effectively the same as locking down your country.'
Mr McNamara pointed to research that found 48 per cent of Britons would be willing to travel within a 'month or two' of coronavirus being brought under control.
Tim Alderslade of Airlines UK said the quarantine was 'just about the worst thing (the Government) could do ... to restart the economy and get aviation and tourism moving again.'
Meanwhile, senior MPs have stepped up their opposition to the plan in its current form.
Speaking to The Daily Telegraph, Conservative chairman of the transport select committee Huw Merriman called for the blanket quarantine to be 'ditched' in favour of other measures such as 'air-bridges, compulsory PPE and temperature testing at airports'.
Former Environment Secretary Theresa Villiers told BBC Radio 4's Westminster Hour: 'I would very much prefer the quarantine rules ... be targeted on flights from Covid hotspots.
People arriving in or returning to the UK will have to give an address where they are intending to isolate for a fortnight, with the officials carrying out spot checks. Pictured is Heathrow Airport
'I think we really do need to find ways to ease travel between this country and other countries like Italy and Spain and France where not only are there important business connections but people do desperately want to be able to take their summer holiday.
'So I appreciate why the Government is bringing in quarantine but I do think that applying it in a blanket way across the board is an over-reaction.
'And my understanding is that the government is actively looking at air bridges and to try to target this requirement in a more focused way and I really hope they're able to do that rather than bringing it in across the board.'