After saying the impact of easing restrictions in England on July 19 had not yet shown up in scientific data, he insisted: “It is very, very important that we don’t allow ourselves to run away with premature conclusions about this. “Step Four of the opening up only took place a few days ago.

       “People have got to remain very cautious and that remains the approach of the Government.” Speaking after a week of self-isolation, Mr Johnson urged people frustrated over the “pingdemic” to follow rules.

       Critical workers alerted by the test and trace app have been allowed to skip quarantine but Mr Johnson said others should stay at home because “everybody understands that this is still a very dangerous disease”.

       He said: “We do need to use the tools that we have. Self-isolation is the one that we’ve got. I urge people to do it.”

       Mr Johnson said that until the test-to-release system arrived on August 16, “please could everybody stick with the programme”. However, he is facing a battle with Tory backbenchers over vaccine passports and a plan to ban non-jabbed students from lecture halls and halls of residence.

       Senior Tory Steve Baker called it an “outrageous proposal” that created a “terrible danger” of splitting the party irretrievably”.