Tory MP Nick Fletcher, who only won his seat in December's election, is against the "blanket restrictions" on people of "all ages, immaterial of the actual risk posed to them".

He suggests instead that people carry out their own "personal covid risk assessment" so they know whether to "shield or go about daily lives" rather than being made to adhere to the rules as one.

Johnson says his backbencher "puts his finger on the heart of the dilemma".

But he says the "tragedy of the coronavirus epidemic is people not badly affected can pass it on unwittingly to older or more vulnerable people".

Former leader of the Green party Caroline Lucas says public consent is dependent on not being forced into financial ruin, and asks for an assurance that the hospitality sector, the arts and the self-employed get the support they need.

Johnson says loans and grants have been extended to "every conceivable sector of the economy - we will of course do more".

He repeats his message that the country has to "push down on the R while allowing the economy to flourish".

Reality Check

The prime minister said: “Yesterday the chief medical officer and chief scientific adviser warned that the doubling rate for new cases could be between seven and 20 days.”

But what the chief scientific adviser Sir Patrick Vallance actually said was: “At the moment we think that the epidemic is doubling roughly every seven days.”

He added: “It could be a little bit longer – maybe a little bit shorter – but let’s say roughly every seven days.”

So it’s not clear where the prime minister has got the 20 days from – doubling over that period would be a considerably different situation.

Rehman Chishti, who resigned from the government last week, external over its latest Brexit bill, thanks the PM for his hard work.

He then asks about "real concerns in the reduction of mental health care provision for those with severe issues during Covid-19".

The Tory MP asks the PM to look into it "urgently" as the consequences could be terrible.

Johnson says the government has been putting extra cash into mental health during the pandemic, and was upping funding overall.

But he promises to look into it.

Will the government apologise for the gross incompetence over testing and over communications that have led to restrictions on people's daily lives, asks Liberal Democrat leader Ed Davey.

And he goes on to ask how will people who are on brink of losing their jobs be supported.

There's no apology, as Johnson replies the plan is to continue to keep the economy moving in the way the government has set out while suppressing the rate of infection and getting the virus down.

Alex Forsyth
Political correspondent

The PM’s spoken repeatedly during this statement about the need to balance the risk to people’s health with the impact of further restrictions on the economy. That reflects wrangling that’s been going on at the very heart of government. Watch closely the reaction from Tory backbenches to see whether the PM’s own party thinks he’s got it right.

Former Tory leadership contender Jeremy Hunt says he understands the PM has taken the decisions "with a heavy heart... but early decisive action now is the best way to avoid second full lockdown later".

But back to testing. He praises the capacity rise, but says: "We are not there yet."

The chair of the health select committee asks Johnson how he can reassure schools when it comes to a lack of tests.

Johnson says he is right to point to the "massive increase" in testing and that the government is now "prioritising teachers".

He says the rates of infection in school pupils are much lower than in the rest of population.

"But I am not going to hide it from him. The future I see for our country and [the key] to defeating this virus is to massively expand testing."

Reality Check

Boris Johnson has asked people who are able to work from home to do so, changing the government’s previous message that workers should be returning to offices.

Nearly half of the UK working population are in, external managerial, professional, or technical occupations that may be considered “white collar”, with jobs that are usually performed in an office and allow greater flexibility for homeworking.

In contrast, the transportation and storage and accommodation and food services industries have only about 10% of people reporting ever working from home.

These sectors have already been severely impacted by lockdown.

Around a third, external of working adults worked from home at times in the week to 13 September. Half of working adults didn’t work from home and travelled to work.

Ian Blackford, leader of the Scottish National Party in Westminster, is now asking for an extension of the furlough scheme beyond the end of October.

There's no direct answer from Boris Johnson, who says his objective is to keep businesses going "as much as we can".

"It's clear what the choices are and what the guidance is. We will continue to support people and businesses who face challenges from coronavirus."

Dame Cheryl Gillan says the PM has achieved "balance and proportionality" in his measures.

But the Tory MP says with the six-month time frame, what does he say to "grandparents who want to live their lives before it is too late", as well as those seeking tests and concerned businesses.

Johnson does not give a message to them, but promises MPs will have their say in a full debate next week.

It comes as a number of his own backbenchers have complained about a lack of involvement from Parliament in the decisions taken by government over the outbreak.

Responding to the Labour leader, Johnson says he is grateful for his support, although it "seems to come and go".

On his criticism of testing, the PM says the UK is testing more than every other country in Europe.

"He is absolutely right to draw attention to the heroic effort of local people" in Leicester to drive the virus down "and that is what we hope to encourage".

And he says the government will "continue to put its arms around the country" when it comes to supporting business.

Johnson adds: "I hope he will also say to everybody in his constituency and elsewhere that this is a balanced and proportionate response."

Alex Forsyth
Political correspondent

Interesting at this point that the government isn’t placing further limits on mixing with other households, as has happened in areas of local lockdown with a high number of cases. However, PM is clear that the government is not ruling out further measures if needed.

Alex Forsyth
Political correspondent

The PM’s admission that the new restrictions are likely to stay in place for six months is a clear shift from Boris Johnson’s optimistic tone of this summer, when he spoke of his hope about a significant return to reality by Christmas.

Starmer says families are concerned there is no clear government strategy, giving the example of people being told to go back to work, and then being told to work from home.

He asks if restrictions will be effective at suppressing the virus. And If they don't work, when will he change them.

What emergency support will be made available to those who will be hit hardest by the measures, he also asks.

These restrictions are necessary but were not inevitable, he says, referring to the troubled testing system.

Labour leader Sir Keir Starmer, back in London after giving his conference speech in Doncaster this morning, is responding to the prime minister's statement.

He says the picture presented by government advisers on Monday, was stark.

"We know from bitter experience what happens next. So it's right the PM is confirming new measures today - and we support them."

Johnson says the government will spare no effort but, if things don't improve, the measures could last for six months.

"This virus is a fact of our lives and I must tell the House and the country our fight against it will continue," he says.

He says he refuses to listen to those who say "let the virus rip" or those who want a permanent lockdown, but wants to take "decisive and appropriate steps to balance saving lives with protecting jobs and livelihoods".

He says it is "tempting to hope the threat has faded and seek comfort in the belief you have avoided the virus so far so are somehow immune.

"But that type of complacency could be our undoing."

Alex Forsyth
Political correspondent

Just a few weeks ago the government was preparing an advertising campaign to get people back to work where safe; now the message is work from home if and where you can. Ministers have consistently argued that the shifting nature of an unpredictable pandemic means having to change guidance quickly, but this will only fuel claims that the public messaging has been confused.

Johnson says the measures "will only work if people comply", and points to those "brazenly" breaking the rules.

As a result, the PM confirms they will be enforced with tighter penalties.

He says the £10,000 fines imposed on those who don't quarantine will now be applied to businesses.

And the penalty for failing to wear a mask or breaking rule of six will double to £200.

Speaking directly to those who shielded earlier this year, the PM says they do not need to shield, except in local lockdown areas.

"If all these actions fail we reserve the right to use greater fire power with significantly greater restrictions," he said.

"I fervently want to avoid taking this step but we will only be able to avoid it if our new measures work and our behaviour changes."

Alex Forsyth
Political correspondent

The PM says a "stitch in time saves nine" – that’s the crux of this argument. Boris Johnson wants to avoid another national lockdown, conscious of the economic and emotional toll it takes. So the thrust of this message is act now to stop that. The question is whether the government’s struck the right balance of risks at this point.

Johnson says the new rule on table service will mean fines if it is broken.

The PM then announces there will be new places where face coverings will be required.

Staff in the hospitality and retail sectors will now need to wear them, as well as passengers travelling in taxis.

The exemptions to the “rule of six” will be cut down. For example, people doing indoor team sports will now not be allowed.

And when it comes to weddings, the limit on guests will now reduce from 30 to 15.

Finally, plans for trials to have the public return to sporting events and conference centres have also been paused.