Boris Johnson has said airport testing may give a “false sense of confidence” as the government considers cutting quarantine time for arrivals from high-risk countries in half.
The prime minister said on Friday that he understands “the difficulties” the airline industry is going through but said testing at points of entry only identifies 7% of positive coronavirus cases.
His comments come after the transport secretary, Grant Shapps, told Sky News the government was looking at cutting the time travellers from higher-risk countries need to self-isolate from 14 days to seven.
Speaking during a visit to Solihull, Boris Johnson said quarantine measures must remain “a vital part” of the fight against coronavirus.
He said: “So 93% of the time you could have a real false sense of security, a false sense of confidence when you arrive and take a test.
“That’s why the quarantine system that we have has got to be an important part of our repertoire, of our toolbox, in fighting COVID.
“What we don’t want to see is reinfection coming in from abroad and quarantine is a vital part of that.”
Ministers are facing pressure from airports and other aviation firms to “get a grip” on the quarantine policy due to the severe economic effects still faced by the industry.
Earlier on Friday, Mr Shapps said that airport testing was not a “silver bullet” that will end the need for quarantine.
Mr Shapps said “I hear the calls”, but admitted: “I’m afraid this coronavirus is just not simple to navigate around and we have to do our best.”
He pointed to France, where he said they had put in airport testing but now “realised the same thing”.
“It isn’t actually the silver bullet solution to this,” Mr Shapps told Sky’s Kay Burley show.
“What you’ve got to do is being able to test further down the line with a period of quarantine as well.”
Mr Shapps did shed light on potentially cutting the quarantine time, saying: “You probably have to have some kind of quarantine period here, perhaps seven or eight days, maybe a test then.
“But these are the thing we’re working through at the moment.”
The British Airline Pilots Association (BALPA) has called on Mr Shapps to approve airport testing as an alternative to 14-day quarantine in a bid to combat the crisis facing the travel industry.
In a letter to the transport secretary, the union said: “Thousands of jobs are being lost, livelihoods are being destroyed and companies are on the edge of survival. The government must do everything it can to support such a vital sector.
“Allowing testing as an alternative to the current 14-day quarantine periods for incoming passengers from higher-risk areas would be a sensible and effective measure.”
Glyn Jones, chief executive of Southend Airport, said an “absence of clear advice from central government” was continuing to “erode consumer confidence”.
While ministers mull cutting the quarantine length, he urged them to act quickly to “put down the sledgehammer” of adding whole countries to the list and “pick up the scalpel” by working on a route-by-route approach.
Wales’ decision to put several Greek islands on its quarantine list instead of the entire country “does demonstrate this can be done”, Mr Jones added.
Heathrow Airport has already set up on-site testing in the hope of letting people get a swab as soon as they land and have the result sent to them within seven hours.
It hopes those who test negative and then do not subsequently get coronavirus symptoms could leave quarantine five to eight days after landing.
Virgin Atlantic announced another 1,150 job cuts on Friday as it said its £1.2bn rescue deal had been completed.
It means the airline’s workforce will be almost half of what it was before the pandemic.