The government has admitted it does not know what proportion of people arriving in the country could have COVID-19, amid calls to start testing people at airports.
Home secretary Priti Patel said she did not have current numbers because the advice from the government’s scientific advisory group Sage was that testing and quarantining arrivals would have a “negligible” impact.
“Their advice has been not to bring in any changes in terms of testing and things of that nature and we’re following that advice,” she said during a Commons home affairs committee meeting on Wednesday morning.
It was revealed during the video conference that 0.5% of the total cases of coronavirus in the UK on 23 March were from people who entered through ports.
But when pushed by Labour MP Yvette Cooper, the government could not give current numbers.
Shona Dunn, second permanent secretary at the Home Office, said: “I don’t have the figure for the proportion coming into the country.
“We will be able to work that out.”
Cooper, who is chair of the home affairs select committee, said: “I don’t understand why the Home Office does not know what that figure is, what that proportion is, that estimate for the number of people coming through our ports and airports.
“Why don’t you have that figure? Why haven’t you been testing and shaping that figure continually as part of your decision-making?”
Latest coronavirus news, updates and advice
Dunn repeated that the government had been working closely with Sage and that it had said testing at ports would not make much of a difference to the pandemic at the moment.
She agreed to try to find out the proportion of people who had possibly entered the country with COVID-19 before the government made the decision not to test and what that number was now.
Patel said quarantine and thermal screening had not been ruled out and could be implemented later, “based on the science”.
There have been calls for tests at airports after it was revealed there were still thousands of people flying into the country.
Heathrow and Gatwick Airport have backed coronavirus checks saying they would reassure people and help to restart the air industry.
Heathrow CEO John Holland-Kaye said: “The crisis came on so rapidly that each country set its own health screening standards, with little coordination.
“Rightly or wrongly, those that require temperature checks are perceived as being safer than others, such as the UK.”
Gatwick Airport CEO Stewart Wingate said he hoped "health passports" that prove travellers are not infected with the virus would help convince people to fly.
Public Health England has previously said temperature checks would not currently be worthwhile, despite other countries using them.
It argued the checks would detect a small number of infections because coronavirus symptoms take up to seven days to show up.
Transport secretary Grant Shapps said last week the policy would be kept under constant review and could change depending on medical advice.
He said thermal testing at ports in countries like the US and Italy did not make a significant impact.
Number 10 said in a statement: “To this point it has been considered that wouldn’t be an effective step to take,”
“We keep everything under review and we do continue to look at what’s happening elsewhere in the world.”