Police will not be carrying out road checks on the border with Scotland and England when quarantine hotels open on Monday.
International travellers landing at Scottish airports from any country will be forced to quarantine in a hotel for 10 days under tough new rules announced last week.
But in England only those arriving from 33 so-called “red list” countries will need to quarantine at agreed residential accommodation.
The differing approaches means passengers could potentially arrive at an English airport and then travel to Scotland by road or rail without the need to quarantine.
Holyrood transport secretary Michael Matheson today accused the UK Government of undermining Scotland’s tougher quarantine rules by failing to help close the loophole.
The SNP minister said border checks between Scotland and England would be “very challenging” due to the volume of traffic each each day.
And the national constabulary has since confirmed it will not be carrying out road checks at the border.
“It’s a loophole that has been created by the UK Government and its failure to take action on the basis of the clinical and expert advice that has been provided on this matter,” Matheson told the BBC.
He added that Holyrood would “continue to press the UK Government” on the matter.
He added: “The danger is that if they don’t act on this matter, they potentially undermine the public health approach here in Scotland. That’s unacceptable.”
Asked about border checks, Matheson said: “The challenge you have with trying to achieve it through border checks between Scotland and England is just the thousands of vehicles that cross that particular route each day.
“It’s something that’s obviously an operational matter for the Chief Constable, but actually trying to operationalise it would be very challenging indeed.
“That’s why the simplest and the safest approach to dealing with this is to have a comprehensive system in place.
“And if the UK Government aren’t prepared to do that, we could resolve the issue by simply ensuring those who are transferring on to Scotland have to go to a quarantine facility near to the airport they arrive at in England.”
A Police Scotland spokesman said: “We have maximised our visibility in communities and on roads across Scotland, including the border area to provide reassurance, deter anyone who might be considering breaching coronavirus regulations and, where necessary, enforce the law.
“We will continue to work with the Scottish Government to support the collective effort to combat the spread of coronavirus.
“At this time there are no plans to establish road checks anywhere across Scotland simply to enforce coronavirus regulations.”