Concerns about border rules have intensified following the detection of the UK’s first cases of the Manaus variant of coronavirus.

Here's everything we know so far.

– The Brazilian variant

The first cases of the Brazilian variant of concern have been detected in the UK, three in England and three in Scotland.

Experts detected the new variant circulating in December in Manaus, north Brazil.

It is not yet known if the mutation causes more severe Covid-19, but evidence suggests it may be more transmissible.

Scientists are conducting analysis to establish if it has a higher mortality rate or if it affects the vaccines or treatments.

HeraldScotland:

The variant was detected in Brazil and in travellers from Brazil to Japan, and contains a unique constellation of lineage defining mutations.

The P. 1 variant is associated with a surge of cases in Manaus late last year, which led to a severe second wave of Covid-19.

Scientists were concerned because this raised the possibility it is able more easily re-infect patients due to the mutations it carries. But the evidence for this is currently limited.

Like the South African variant, the Brazilian one carries a mutation in the spike protein called E484K, raising concerns that vaccines may not be as effective against it.

– How did these cases arrive?

The identified cases involved people flying from Brazil to the UK via Paris or Zurich.

The three Scottish cases were found in asymptomatic passengers who flew into Aberdeen on the BA1312 flight from London Heathrow on Friday.

READ MORE: 'Scotland-level' search underway to trace people who shared plane with Brazil-strain infected trio

They tested positive while self-isolating and contact tracing of other passengers on the flight is currently ongoing.

– What questions does this raise about quarantine?

Some people believe arrivals from Brazil should have faced tougher measures earlier than they did, including the requirement to quarantine in a hotel.

– When did we know about the Manaus variant?

The variant was detected in Brazil and in travellers from Brazil to Japan in January.

It is linked to a surge of cases in Manaus late last year.

– What did the UK Government initially do?

Direct flights from Brazil to the UK have been banned since January 15.

But UK nationals or residents have continued to be allowed to return via indirect routes as long as they quarantine for 10 days.

Initially there was no mandatory testing on arrival.

– Was this controversial?

Arrivals were allowed to travel to their home or another location to begin their self-isolation.

It is likely that many people made this journey on public transport, mixing with the general population.

– What has changed?

The requirement to enter a quarantine hotel was introduced on February 15.

Since that date, arrivals have also been required to take a coronavirus test on days two and eight of their self-isolation period.

– What are people saying about the Government’s response?

Labour MP Yvette Cooper, who chairs the Home Affairs Select Committee, said the situation highlighted “gaps” in the system.

She told the Today programme that the Government should be “learning lessons” from countries such as South Korea, that have extra precautions including testing of arrivals at airports.

Health Secretary Jeane Freeman said the red list system for quarantining international arrivals is “inadequate”.

The Health Secretary said the issue of international travel remained the main area of contention with the UK Government.

READ MORE: 'No reason' to think Brazilian variant circulating in Scotland as passengers traced

All international passengers arriving at Scottish airports must enter the hotel quarantine system, whereas the UK Government only requires this of those coming from countries on the “red list” – most of which are in South America and Africa.

A Scottish Government advisor, Professor Devi Sridhar of Edinburgh University, said in a tweet the arrival of the new variant showed the red list approach “doesn’t work”, as the passengers in question arrived in the UK via Paris.

Ms Freeman said she agreed with Prof Sridhar’s assessment, saying: “That’s why the Scottish Government has consistently argued that the red list as the sole means of introducing and providing managed quarantine is inadequate.”

She said international travel continues to be the “main area that we seek to persuade the UK Government to take steps on”.

– What is the Government saying?

Vaccines minister Nadhim Zahawi insisted that the UK’s border controls are “pretty stringent”.

He told BBC Radio 4’s Today programme: “Even countries that had hotel quarantine, like Australia, still have to deal with the variants actually challenging them in the same way they challenge us.”

Scotland’s national clinical director said he was “not panicking, but concerned” about the discovery of a Brazilian coronavirus variant in the UK.

HeraldScotland:

A total of six cases of a mutated form of Covid-19 first detected in Manaus, Brazil, have so far been discovered in the UK: three in England and three in Scotland.

Professor Jason Leitch said enhanced contact tracing and testing has been introduced in an attempt to “interrupt chains of transmission” but he was confident there had been no community spreading in Scotland.

“Three travellers from Brazil – via quite a circuitous route – had symptoms, while they were self-isolating, so there’s no suggestion they had symptoms on the plane or were involved in lots of contacts,” Prof Leitch told the BBC’s Good Morning Scotland programme.

He continued: “It’s the first time we [have found] this particular Brazilian strain in Scotland, and that worries us a little bit, but people shouldn’t get too concerned. [There is] no community spread, no evidence it’s gone anywhere else.

“And the reason why we’re worried scientifically is we’re not absolutely certain that this version is amenable to the natural immunity some people already have and the artificial immunity we’re creating with vaccination.”

HeraldScotland:

Jeane Freeman said there is no reason to believe that the Brazilian strain of Covid-19 is in circulation in Scotland but efforts to “identify and break any possible chains of transmission” are ongoing.

Ms Freeman told the Scottish Government’s daily Covid-19 briefing: “If you were on that flight and have not yet been contacted, you will be contacted shortly, so please wait for that.

“I want to stress that there is currently no reason to believe that the P1 variant of the virus is in circulation in Scotland, however, I hope this summary reassures you that we are doing everything we can and everything necessary to check whether this variant of the virus could have been transmitted within Scotland and to identify and break any possible chains of transmission.”

READ MORE: Jason Leitch - 'Concern but no panic' over Brazilian Covid variant

She added: “We know that current vaccines are effective against the strains of the virus which have already been established in the UK.

“However, more work is required to determine that this remains the case for emerging strains of the virus, such as the one we are highlighting today from Brazil.”