There's a question about who will identify whether local areas will have to be locked down, and how it will be enforced.

Matt Hancock says directors of public health will have a "critical role to play".

Dido Harding says higher-tier local authorities will be responsible for reporting local flare-ups.

But she says a "national effort" will also be required to make the system work.

Ella from Maidenhead asks about evidence those under 45 are at significantly lower risk of death from Covid-19. So, she asks, could we see lockdown restrictions targeted at particular age groups?

Matt Hancock responds saying the evidence shows those under 45 are still as likely to get it and transmit it.

Prof Tam says it is true the death rate is very age-dependent and although steeply rising after 60, there are still some under-45s at very high risk.

He says the aim is to reduce contact between people and households to a level that is safe.

There's a question from a member of the public, on whether the UK is learning lessons for the next pandemic it will face.

Matt Hancock says it is important to learn "as much as we possibly can" to prepare for future outbreaks.

He says ministers are "learning all we can" from the spread of Covid-19.

Image source, Getty Images

Health Secretary Matt Hancock has set out details for the test and trace system, which will start tomorrow in England.

If you test positive for coronavirus, you will be asked to provide details of people you have come into close contact with.

Close contacts will then be told to stay at home for up to 14 days, even if they do not have symptoms, to stop them from unknowingly spreading the virus.

To find out more about how it will work, read our guide here.

Baroness Harding says she's spoken to a huge number of people in the past weeks and has heard "real support and a desire to make this work".

Thanking NHS staff and everyone who has signed up to be a contact tracer, she said it is one of the most ambitious and complex programmes "any of us" has ever worked on.

Image source, Downing Street

Jonathan Van Tam, deputy chief medical officer for England, says the "gradual increase" in car use has continued.

But he says there is evidence in the latest data that people are continuing to stay away from public transport.

Pointing to the slide above, he says there has been a "continuing decline" in hospital admissions.

There are 8,879 people in UK hospitals with Covid-19, he adds, down from just over 10,000 at this time last week.

Baroness Dido Harding, chair of the coronavirus test and trace programme, says she wants everyone to feel safe and confident to take part in the scheme.

She outlines the three steps involved:

1: If you have one or more of the symptoms of coronavirus - a fever, cough, loss of sense of taste or smell - you must isolate

2: Then book a test on the NHS/coronavirus site or dial 119. If you test positive, you'll be contacted by the NHS test and trace service within 24 hours

3: The service will help you establish who you've been in contact with, and could have infected

Matt Hancock says those who have been in contact with symptomatic people will be told to self-isolate, even if they themselves do not have symptoms.

He acknowledges this will be a "big ask" but calls on people to follow the advice for the “safety of everyone".

He adds that there will be "bumps in the road" but says contact-tracing will improve over time.

He says the system is "not the whole answer" but an important tool when it comes to making lockdown measures more "targeted".

The Health Secretary says all people with symptoms of coronavirus will now be eligible to get a test regardless of their age.

Previously, this blanket availability was not offered to the under-fives.

He says the UK now has the "capacity" to conduct 161,000 tests per day.

Matt Hancock says the test and trace programme launching tomorrow will allow the government to replace a national lockdown with "local action" - instead of locking many people down, isolating a few.

He says the programme will allow the UK to "thwart" and "ultimately defeat" the spread of the virus.

The UK government press conference now begins.

Matt Hancock says the rollout of the test and trace scheme in England tomorrow is an “incredibly important milestone”.

He confirms the additional 412 deaths after a positive test reported earlier, taking the UK total to 37,460.

He says yesterday’s figure for tests was 117,013 – this official number includes kits sent out to homes and test centres.

Reality Check

Boris Johnson was asked about the risks patients who were discharged from hospital without being tested for coronavirus posed to care homes.

The prime minister said discharges were clinical decisions and said “in no case did this happen when people were suspected of being coronavirus victims”.

On 2 April the rules on discharging to care homes, external were clarified, saying "negative [coronavirus] tests are not required prior to transfers/admissions into the care home".

Those with positive tests could also be discharged, with necessary precautions.

It wasn’t until 15 April that the government said all patients, external discharged from hospitals would be tested for Covid-19.

By this time, more than 5,700 residents in England and Wales had died, either in their care homes or in hospital.

NHS Providers, which represents hospitals, denies patients with coronavirus were “systematically” discharged to care homes but says it’s possible “a very small number” who were not displaying symptoms (and whom hospitals hadn’t been able to test) were.

Read more here.

"This has been of great benefit," says Bernard Jenkin, bringing the session to a close. He urges the PM to come back to the committee before the summer.

Johnson says that while he has enjoyed the questioning, they take a lot of preparation and the government is already working "flat out" to beat coronavirus.

And there the committee ends.

But stick with us for the daily UK press conference - led today by Health Secretary Matt Hancock.

Sir Bernard raises points from members who are not present, asking firstly about what is being done to help the hospitality industry.

Johnson says the government is "really trying to go as fast as we can".

He says, while it is "really difficult to bring forward hospitality measures in a way that [adheres to] social distancing", he is "much more optimistic than [he] was that we may be able to do things faster".

Sir Bernard also says it "seems to take a long time for lessons to be learned" on the tackling of coronavirus, and asks on behalf of another committee chair whether having a headquarters to deal with the virus would help.

But the PM doesn't agree, saying the operation in No 10 is working well.

Labour's Yvette Cooper returns to the question of whether the UK should have quarantined earlier and asks if the government will publish the scientific advice for that decision.

The PM replies that Sir Patrick Vallance, the government's chief scientific adviser, has said all advice from Sage, the group of scientists advising the government, will be published.

He adds that all decisions were taken "in good faith".

Labour's Meg Hillier comes back in to say the PM has been "clear he wants to be focusing on the agenda" and "stress the vital message".

But she asks if the message has become unclear since the controversy over Dominic Cummings.

Johnson says no, adding: "I think the message during lockdown was very clear and people who had the virus, including my adviser, isolated for 14 days and people stayed at home."

Hillier interjects, saying she has been contacted by numerous people who didn't know they could do what Cummings did.

Johnson says: "I think the most important thing is for everybody to focus on next steps.

"I really dispute [that the message is unclear] as I am looking at the figures every day, seeing continual compliance by the British public, as they understand [it] requires common sense."

Merriman goes on to ask what the PM thinks of British Airways putting employees on the furlough scheme but threatening them with redundancy.

Johnson says he doesn't want to go into the actions of individual companies, but adds: "People should not be using furlough to cynically keep people on their books and then get rid of them."

The PM says the government is "looking at what we can do".

Huw Merriman from the transport committee asks why the UK did not start quarantining people coming from abroad earlier.

"The scientific advice was very clear it would make no difference," replies the PM.

He says the UK is doing it now because "we don't want to see re-infection".

He adds that "air bridges" with other countries could be agreed if the UK makes progress in reducing the infection rate.

Jessica Parker
BBC political correspondent

Conservative rumblings for Dominic Cummings to go had quietened down this morning.

So Number 10 might not be delighted to see that a couple more have emerged as this afternoon’s committee hearing takes place.

Mid Derbyshire’s Pauline Latham has posted that she has decided to make her view known to the PM that she thinks Cummings should resign.

And Giles Watling, who says he’s listening to the Liaison Committee, clearly isn’t convinced either.

The Clacton MP says he has also concluded that the chief aide should stand down, calling Cummings’ continued presence an “unwanted distraction”.

I’m just quickly doing the maths but that looks to put the total of Tory MPs who’ve publicly said it’s time for Dominic Cummings to go at around 40.

With the PM's appearance at the Commons Liaison Committee running slightly longer than scheduled, there will be a bit of a delay to the daily UK government press conference.

It had been due to start at 17.30 BST - but stay with us and we will bring you the latest updates here as we get them.