BORIS Johnson warned the coming months will "test the mettle of this country" as he unveiled a three-tiered Covid alert system for England.

The Prime Minister told MPs: "This is not how we want to live our lives.

"But is the narrow path we have to tread between social and economic costs of a full lockdown and the massive human and indeed economic cost of an uncontained epidemic.

"I must warn the House the weeks and months ahead will continue to be difficult and will test the mettle of this country. I have no doubt at all that together we will succeed."

Johnson faced more than 100 questions over two hours in the House of Commons yesterday as MPs pressed him on his handling of the pandemic and the very real impact on the public.

There are now more coronavirus cases in the UK than there were at the outset of lockdown in March.

Johnson says that helped limit the spread of the illness, but that another complete lockdown would "do such damage to our economy we would erode our long term ability to fund the NHS and other crucial services".

Most of England is, under plans set to be voted on by MPs tomorrow, set to go onto the "medium" alert level, which is in line with current national guidelines. Where transmission rates are rising most rapidly, a “very high” alert level will be put in force, with garden meet-ups banned and pubs shut.

Johnson, who himself contracted Covid-19, cautioned against a blase attitude to the virus amongst younger people, saying that though the elderly are most at risk of dying from the illness, "there will still be many younger people for whom alas it remains lethal".

Though he said there is a "good chance" of a vaccine being developed, Johnson warned that this"cannot be taken for granted". He said: "Sars took place 18 years ago, we still don't have a vaccine for Sars."

However, despite the rising number of positive cases, he stated: "With all the lessons we have learned in the past few months, we are getting better and better at fighting this virus."

SNP Westminster leader Ian Blackford warned against delays in Covid-19 testing and suggested a u-turn should come via an extension of the full furlough scheme to help workers.

He told the Commons: "We know we're at a tipping point, so today must be a turning point – a turning point where we must once again act collectively and get back to the absolute priority of suppressing the virus, protecting the NHS and saving lives."

But Tory MP Philip Davies urged Johnson to "once again put his trust" in Britons instead of instigating "a constant blizzard of arbitrary rules which will only serve to collapse the economy and destroy businesses and jobs".

Johnson replied: "The best decision that individuals can make for themselves, for their families and for communities is to follow the guidance, wash your hands, face, space, protect the NHS and save lives."