Travellers required to quarantine in government-sanctioned hotels could end up paying an extra £1,200 if they test positive for coronavirus towards the end of their stay, it has been revealed.
Anyone arriving in the UK who has been in one 33 "red list" countries in the last 10 days now has to self-isolate for 10 days in a quarantine hotel at a cost of £1,750.
It has now emerged that extra charges will apply to guests who are required to extend their stay beyond the initial period as the result of a positive COVID-19 test.
Information on the £152 daily cost of longer quarantine stays was published on the government's website on Monday - after some guests had started checking in.
Guests can leave quarantine after 11 nights if they get a negative result from tests taken on the second and eighth days of their isolation.
But if someone returns a positive result from the first test, they will have to stay in quarantine for a further two nights at a cost of £304.
And a positive result from the second test will mean the guest has to stay in the hotel for another eight nights at a cost of £1,216.
Asked what will happen if someone cannot afford the extra fees, Prime Minister Boris Johnson told a Downing Street news conference: "It is currently illegal to travel abroad for holidays anyway.
"We would expect people who are coming in from one of these red list countries to be able to cover their costs."
The 33 countries on the "red list" includes Portugal, the United Arab Emirates, South America and southern Africa.
Scotland has opted to require arrivals from all countries to isolate in a quarantine hotel, unless they have travelled from the Common Travel Area, which includes the UK and Ireland.
UK and Irish nationals and UK residents going back to England who have been in a "red list" country in the last 10 days still have to isolate even if they have come back via the CTA.
Scotland's CTA exemption allowed a father and daughter who had entered quarantine to leave just one day into their isolation and complete it at home.
Speaking to BBC Scotland, Chun Wong said he and his daughter flew back to Scotland from the United States via Dublin, and went straight to a hotel at Edinburgh Airport.
"I received a call from reception saying a gentleman from the airport would like to talk to me," Mr Wong explained.
"He said that since I landed in Dublin first and then got a connecting flight to here, I was not required to quarantine in a hotel.
"I still have to quarantine and do the self-testing kit on the second and eighth day, but they said it was an error on their part."
Nicola Sturgeon, Scotland's first minister, has previously expressed concerns that England's quarantine requirements do not go far enough.
"It would be better if we had that four nations approach, or at least a three nations approach where the border of the island that Scotland, England and Wales share, had the same provisions in place," she said on Monday.