Mr Johnson today announced the most wide-ranging lifting of the lockdown yet, with swathes of businesses able to reopen from July 4 and families able to visit each other at home.
Addressing the public directly at the final daily Downing Street briefing, he said: “The Government has asked a huge amount of all of you, and… the people of this country met that challenge with good humour and common sense.
“Of course the fight is far from over. This is a nasty virus still that wants to take advantage of our carelessness.
“I’m afraid there will be local outbreaks. And I must tell you that if the virus were to begin to run out of control, I will not hesitate to put on the handbrake and reverse some of these changes at local or indeed national level as required.
“But we can avoid that if we all continue to stay alert and do our bit to control the virus.”
It comes as a further 171 deaths of people who had previously tested positive for coronavirus were recorded today, bringing the total number of UK deaths to 42,927.
In Yorkshire, 2,787 deaths have been recorded, with an additional six added today.
Chief Medical Officer for England Professor Chris Whitty urged businesses and individuals to take the new guidelines, including the reduction of the two-meter rule, seriously.
He said: “To be really clear, it is absolutely critical that every individual, every household and every firm takes these precautions seriously.
“If that does not happen, we will go back to a situation where transmission starts to rise again.”
He warned: “If people hear a distorted version of what’s being said, that says ‘this is all fine now, it’s gone away’ and start behaving in ways that they normally would have before this virus happened, yes, we will get an uptick for sure.
“It is absolutely critical people stick to the guidance that has been given, it’s a changed guidance for there are still very significant restrictions socially and there are very significant restrictions on business of different sorts.”
And he predicted that the country could have to cope with Covid-19 into 2021.
He said: “I would be surprised and delighted if we weren’t in this current situation through the winter and into next spring.
“I think then let’s regroup and work out where we are.
“I expect there to be a significant amount of coronavirus circulating at least into that time and I think it is going to be quite optimistic that for science to come fully to the rescue over that kind of timeframe.”
Earlier, Batley and Spen Labour MP Tracy Brabin asked the Prime Minister about local outbreaks. She said: “My concern is with the Government’s easing of lockdown we will see these localised outbreaks. With the Health and Safety Executive having its budget cut by 50 per cent since 2010, can the Government ensure that Kirklees and other councils will have all the money they need to keep our communities safe?”
She also asked the Government to look into any link with meat manufacturing premises, after the outbreak at Kober Ltd in Cleckheaton last week.
Mr Johnson said: “Local councils will be fortified in implementing local lockdowns by central Government and the Joint Biosecurity Centre so that we are able to crack down very efficiently on these flare-ups as they happen.”
Hull North Labour MP Dame Diana Johnson asked the Prime Minister: “What is the public health message that the Prime Minister is conveying by opening pubs ahead of the full opening of schools?”
Mr Johnson said: “I think that most people will understand that we want as much of our business sector and economy to open as possible, in a covid-secure way. [Dame Diana] will also understand that we want our schools to open in a safe way.
“That is why we have done what we have done and made the announcements that we have made. It has only been possible to open schools to some classes before the summer break, alas; but we are ahead of many other countries in Europe in doing so.”
Following a question from Conservative MP for Harrogate and Knaresborough Andrew Jones, Mr Johnson also urged councils to be flexible in allowing businesses such as cafes to place tables on pavements.
Scarborough and Whitby Tory MP Robert Goodwill added: “This statement will be widely welcomed in Britain’s premier resort, Scarborough. I hope that Scarborough will very soon be firing on all cylinders.”