Nicola Sturgeon has refused to rule out shutting the Scottish border to prevent people using a loophole to avoid strict quarantine rules.
Scotland has imposed stricter restrictions on international travel, forcing all arrivals to pay £1,750 to quarantine in hotels for 10 days from Monday.
In England, only those who are coming back from 33 “red list” countries such as Portugal and South Africa, must undergo a 10-day hotel stint.
The discrepancy sparked fears that some Scots could exploit the loophole by flying into England and then travelling north of the border by car or public transport.
Visitors would still have to self-isolate for the 10-day period, but they would not have to do so at one of the designated hotels.
The First Minister said she wanted a UK-wide approach to quarantine rules.
Asked if she could close the border if that doesn’t happen, Ms Sturgeon told a coronavirus briefing: “I do not rule it out.
“I would like to have the most effective system in place here. I’m not sure it is the best solution, if it is the only one I can put in place then it may come to that but why let someone travel half way across the UK before you do that.
“It would be better if we had that four nations approach – or at least a three nations approach where the border of the island Scotland, England and Wales share had the same provisions in place.
“I’m trying to be constructive here… I want us to try to come to the best solution possible.”
Health Secretary Matt Hancock said he was “happy to have conversations” with the Scottish Government about providing quarantine facilities for people arriving in England, before heading home to Scotland.
Downing Street insisted Scotland’s rules only apply once passengers have travelled north of the border.
The Prime Minister’s official spokesman said: “If travellers arrive in England from a red list country and wish to continue to Scotland they will first need to complete 10 days in managed quarantine in England.
“If a traveller arrives in England from an amber list country and wishes to continue to Scotland they will be able to do so but will then fall under Scottish quarantine rules on entry.”
It comes after a significant number of people due to take the first flight into Scotland since the new rules came in on Monday did not board the plan.
The first international flight, which left Istanbul, Turkey, for Edinburgh on Monday morning had been due to carry around 65 passengers but fewer than five made it on board.