Britain has announced tough new measures to curb the spread of coronavirus variants from abroad, including steep fines and even jail time for those who break the rules.
The country has been one of the worst affected in the global health crisis, with some 113,000 deaths, and is banking on a mass vaccination drive to cut infection rates.
But fears have grown over new variants of the virus, including a South African strain that may be more resistant to new vaccines.
Now, travellers who already must show evidence of a negative test 72 hours before their trip will have to take two Covid tests during a mandatory 10-day quarantine period.
The tests will have to be taken on days two and eight of self-isolation after arrival, with any positive result adding 10 more days to the confinement.
Health Secretary Matt Hancock told parliament that British or Irish residents arriving from 33 countries deemed high risk of new variants will have to stay in one of 16 designated hotels in England.
Travellers will have to stay in their rooms, have meals delivered to them and pay out their own pocket at a cost of £1,750 (approx €2,000).
He said he did not want to see Ireland acting as a back door to another country.
High-risk countries include South Africa and all South American nations. All travel from there is currently banned for non-British residents.
A recent South African study indicated the Oxford/AstraZeneca vaccine did not prevent mild or moderate forms of the variant circulating there - of which 147 cases have been found in Britain so far.
However, Prime Minister Boris Johnson said on Monday he was confident that all vaccines being used against the strain were "effective in delivering a high degree of protection against serious illness and death".
Some indications that announcement of tighter border controls in Britain will lead to more restrictions here around international travel. Government sources saying that Irish officials are in constant contact with officials in London and greater restrictions here are expected— Mícheál Lehane (@MichealLehane) February 9, 2021
The Scottish government announced a similar "managed isolation" scheme, with 1,300 rooms at six designated hotels. Both come into effect from Monday.
Matt Hancock told MPs he made "no apologies" for the tougher measures, which critics have said come too late to restrict the spread of new variants and do not go far enough.
But the scale of the sanctions indicated the threat the government believes new variants pose to its vaccination programme, which has so far seen some 12.2 million people receive jabs.
Anyone refusing to take tests risks a fine of between £1,000 and £2,000, while those who do not self-isolate could have to pay between £5,000 and £10,000.
Travellers found to have given false information about being in a "red list" country 10 days before travel could receive up to 10 years in prison.
"People who flout these rules are putting us all at risk," Mr Hancock said.
"Passenger carriers will have a duty in law to make sure that passengers have signed up for these new arrangements before they travel and will be fined if they don't."
The restrictions will be eased "as practicable and as soon as is safe", he added.
The British government has so far reserved 4,600 rooms for hotel quarantine under the programme, and said it would book more if necessary.
Britain has been under lockdown since early January to combat a surge in cases that have pushed health services to breaking point.
The government has set a target of vaccinating 15 million of the most vulnerable before 15 February, which could pave the way for a lifting of restrictions.
Spanish travel bans extended
Spain has extended a ban on arrivals by air from Britain, Brazil and South Africa until 2 March over the new virus variants detected in those nations.
Only legal residents or nationals of Spain and the neighbouring micro-state of Andorra are currently allowed in on flights from these countries.
The restriction on arrivals from Britain was imposed at the end of December while the ban on arrivals from Brazil and South Africa came into effect on 3 February.
Spain's cabinet agreed on Tuesday to extend these entry restrictions for another two weeks, Health Minister Carolina Darias told a news conference.
This is the fourth time that Spain has extended its restrictions on arrivals from Britain.
Spain on Friday confirmed the first case of the Brazilian variant while at least two cases of the South African variant and 479 cases of the British one have already been detected.
Officials predict the British variant could become the dominant strain in Spain by March.
Spain has been hard-hit by the pandemic, recording over 62,000 deaths from nearly three million cases so far.