Few of Boris Johnson's policies for tackling coronavirus have had such a chaotic gestation as the plan to quarantine all arrivals in the UK.
Several ministers, including members of the Cabinet, have privately expressed opposition to the idea, while prominent Tory MPs have publicly campaigned against it.
Meanwhile, "air bridges" to avoid quarantine, the brainchild of Grant Shapps, the Transport Secretary, was announced, rubbished and then reannounced over the course of four days.
Now doubts have emerged even within No 10, with Mr Johnson himself rumoured to be looking for ways to wind down quarantine quickly, within the bounds of scientific advice.
The 14-day quarantine period, first revealed by The Sunday Telegraph in April, was confirmed by the Prime Minister in his address to the nation on May 10, when he said he was "serving notice" it would soon be necessary.
Later that week, Matt Hancock, the Health Secretary, said holidays abroad would "not be possible this year" due to the tough restrictions.
There was a different message from the Government on May 18 as Mr Shapps told a committee of MPs that ministers were discussing air bridges as a way of avoiding the need for quarantine between selected countries.
He said the idea would be for "people from other countries who have themselves achieved lower levels of infection to come to the country".
But Downing Street poured cold water on the air bridges idea the next day, saying it was "not government policy".
Whitehall sources said that Mr Shapps had been "freelancing" and had gone public with the idea "because he's got the airlines on his back".
Dominic Cummings, the Prime Minister's chief adviser, is understood to have been one of the architects of the quarantine plan, and government sources briefed newspapers that members of the Government were "annoyed with" Mr Shapps for what he had done.
However, four days after Mr Shapps had introduced the idea of air bridges, they were back in vogue. Priti Patel, the Home Secretary, said quarantine would come into force on June 8, and people who refused to self-isolate would face fines of £1,000.
Slipped on to the bottom of the official announcement was confirmation: "The Government will continue to look at options and these will include air bridges - agreements between countries who have low transmission rates to recognise each other's departure screening measures for passengers, and removing the need for quarantine measures for incoming passengers."
Whitehall sources quickly refined its language so that air bridges became "travel corridors", to incorporate the fact that Ireland would be exempt.
The message over other exemptions was muddled. Downing Street said the rules would not apply to France "at this stage", which was read by many as a blanket exemption for the French. In fact, the only reason it did not apply to the French was because it did not apply to anyone at that stage.
With other countries in Europe easing their own travel restrictions, many in government believed the policy was ill-timed, wrong-headed and would punish British travel firms and airlines by handing trade to their rivals.
Ms Patel also faced questions about why, if the policy was so vital, it was not being implemented until June 8.
Last week, on ITV's This Morning, Mr Hancock added to the uncertainty when he was asked if the Government might "rethink" the plan, and replied: "I wouldn't rule it out." He also abandoned warnings about summer holidays being impossible, saying he would not rule out foreign holidays in July.
Mr Cummings, of course, has had other things on his mind and the scandal surrounding his trip to Durham during lockdown is said by some in government to have weakened him.
"People just aren't scared of him any more," one source said. "Everyone knows that he is one wrong move from being out of a job now."
It may be no coincidence that the quarantine plan he has championed is already being watered down.