BORIS Johnson has denied English MPs weren't invited to a coronavirus briefing about new Northern restrictions. 

The PM said his team have been talking to local governments "for days and days and days".

Labour MP for Wigan Lisa Nandy and Stockport MP Navendu Mishra said they were not invited to a discussion on the matter.

READ MORE: English MPs not invited to 'shambolic' briefing on Northern lockdown restrictions

At the PM's coronavirus update, a journalist from the Liverpool Echo said local politicians only heard about plans to shut pubs in the press and that local MPs only had 10 minutes warning for this afternoon's meeting.

Johnson responded: "Just on your point about Liverpool City Region, I talked to [mayor] Steve Rotheram yesterday about what we were doing and he was at the Cobra meeting today to green light the proposals.

"My team's been talking to local government across the country for days and days and days and we will continue to do so because I do think that the package of measures, if we implement them all, as Chris has said very effectively, if we implement Tier 3 properly in the way it needs to be done I do believe we can drive the R down in the way that we need to do."

Johnson went on to say that Covid-19 cannot be allowed to “rip” through the population as he outlined a three-tiered Covid alert system for England.

READ MORE: Boris Johnson's 'test the mettle' Covid warning as three-tier English system set out

Alluding to the concept of herd immunity, Boris Johnson said this strategy would see an “intolerable” death toll from Covid-19 and put such a “huge strain” on the NHS that it would not be able to treat any other condition.

He said the idea of letting the virus “take hold” among the young and fit while shielding the elderly and vulnerable was “no answer”.

It comes as the World Health Organisation (WHO) said that herd immunity for Covid-19 is “unethical” and “not an option”.

Herd immunity occurs when a large portion of a population becomes immune to a disease.

The concept is gaining popularity among some, including a group of scientists who have signed the so-called Great Barrington Declaration.

The declaration, which is earning thousands of signatures from medical professionals, academics and the general public, calls for a herd immunity approach to tackling the Covid-19 pandemic while protecting the most vulnerable populations.

It suggests that people who are less vulnerable to the effects of Covid-19 should be allowed to return to normal life.

In his speech to the Commons, Mr Johnson said: “There are those who think that the patience of the public is now exhausted, that we should abandon the fight against Covid, stand aside, let nature take her course and call halt these repressions of liberty.

“And of course I understand those emotions, I understand the frustration of those who have been chafing under the restrictions, the sacrifices they’ve made.

“But if we were to follow that course and let the virus rip, then the bleak mathematics dictate that we would suffer not only an intolerable death toll from Covid, we will put such a huge strain on our NHS with an uncontrolled second spike that our doctors and nurses would be simply unable to devote themselves to other treatments for cancer, heart disease, hundreds more that have already been delayed.

“And that would be delayed again with serious long term damage to the health of the nation.

“And I’m afraid it is no answer to say that we could let the virus take hold among the young and fit while shielding the elderly and vulnerable, because the virus would then spread with such velocity in the general population that there would be no way of stopping it from spreading among the elderly.

“And even if the virus is less lethal for the under 60s there will still be many younger people for whom, alas, it remains lethal.

“We don’t want to go back to another national lockdown.

“We can’t let the virus rip.

“And so we’ve followed since June, a balanced approach.”