Home Secretary Priti Patel told Tory supporters that she argued for the UK border to be shut to international visitors in March when the pandemic first emerged.
The comments, said to have been made to the Conservative Friends of India group, are contrary to her public defence of the Government’s decision not to enact a full arrivals shutdown.
In comments first reported by political website Guido Fawkes, Ms Patel said: “On ‘should we have closed our borders earlier’, the answer is yes. I was an advocate of closing them last March.”
But the Tory leader evaded the question on Wednesday, instead opting to criticise Labour’s own policy on border controls.
Mr Johnson said: “I think it was last March that (Sir Keir) along with many others was actually saying that we didn’t need to close borders but as usual Captain Hindsight has changed his tune to suit events.”
The Prime Minister argued that the UK had now “instituted one of the toughest border regimes in the world” with its insistence that travellers have a negative test before arrival and then self-isolate for a period.
In mid-March, the UK abandoned asking people to quarantine for two weeks after arriving from areas with high infection rates, such as Hubei province in China and Italy.
The decision was in contrast to many other countries, such as New Zealand, which has been widely praised for getting the pandemic under control, partly through strict quarantine measures for arrivals.
The UK Government introduced blanket quarantine restrictions in June for all international travellers, except those coming from Ireland, while “travel corridors” with countries deemed to have safe levels of infection were established a month later.
Ministers this week suspended all travel corridors and introduced new rules requiring arrivals to produce a negative coronavirus test taken up to 72 hours before departure and to self-isolate for up to 10 days after entering the UK, in a move designed to prevent new strains of Covid-19 entering the UK.
On Wednesday, Ms Patel continued her public defence of the actions taken, telling broadcasters that ministers had followed scientific advice over border controls.
She told BBC Breakfast: “Government has listened to a range of advice and followed advice from professionals and advisers – medical and scientific – from day one of this pandemic and there has been collective decision making across the board.
“When it comes to border measures, for example, there was a lot of work that took place last year, both in transport and in the Home Office, but also working with the scientists who advised us at the time when coronavirus was incredibly high that it would not have made a difference to have taken border measures.”
Labour’s shadow home secretary Nick Thomas-Symonds said: “This is a shocking admission from the Home Secretary about the Government’s failure to secure the UK’s borders against Covid.
“Priti Patel’s admission, coupled with the complete lack of strategy for testing of travellers, means that the Government has left our doors open to the virus and worrying mutations.
“Ministers now need to – urgently – review and overhaul border policy, whilst taking responsibility for the huge damage their incompetence has done to our national safety and security.”
A Home Office spokesman said: “We have strong measures at the border in place which are vital as we roll out the vaccine.”
The Prime Minister’s official spokesman said: “I’m not going to get into the detail of private conversations, but I would point back to the measures that we have introduced to ensure that we are not allowing the virus to be reimported into the UK given the hard work that the public has undertaken to suppress and try and control the virus.”
Mr Johnson still has full confidence in his Home Secretary, the spokesman added.