We finally know more about Boris Johnson's coronavirus response after crucial scientific documents were revealed to the nation.
More than a dozen papers have been published that show exactly how the government's scientific advice during the pandemic unfolded.
The documents from SAGE (Scientific Advisory Group for Emergencies) show Boris Johnson finally imposed the lockdown after he was warned intensive care would fill up within a fortnight.
And he boasted he was shaking hands with "everybody" - on the same day experts said he should tell the public to stop shaking hands.
The papers are a crucial revelation because the PM has always said he's "guided by the science".
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They show this is more or less true. But the documents also show the science is never one clear piece of advice.
And in a few cases, the government's action did not match up with what the documents say.
For example, scientists appeared to say they were happy with a London-only shutdown of bars and restaurants rather than a UK-wide closure.
But the government, after days of debate, went with a UK-wide shutdown instead.
Meanwhile, the documents clearly spell out the dangers in the next phase when lockdown begins to ease.
They warn any easing of lockdown must be "very gradual" - and give people back some of their leisure activities, not just restart the economy.
And the scientists warn rogue bosses could exploit any system of "immunity passports" to hand riskier jobs to those who've already had Covid-19.
Here are 9 things we've learned today.
1. Boris Johnson imposed lockdown after he was told ICU would fill up in 11 days
Boris Johnson took his lockdown decision after being warned intensive care beds would fill up in 11 days.
A "consensus view" on March 20, from the Scientific Pandemic Influenza Group on Modelling, warned the virus was doubling every three to five days.
It said: "It is very likely that we will see ICU capacity in London breached by the end of the month, even if additional measures are put in place today.
"The rest of the UK is 1-2 weeks behind London. In the absence of additional measures being put into place in the next few days, it is likely that we will breach ICU capacity in other regions."
The Prime Minister - who had stopped short of a full lockdown - then announced one on March 23.
SAGE warned even a lockdown would not stop capacity being breached, because it would take two to three weeks to take effect.
But the NHS then announced the first of its Nightingale hospitals on March 24 - which meant the first peak did not exceed intensive care capacity.
2. Boris Johnson boasted about shaking hands - on the same day scientists said not to
Boris Johnson boasted he'd shaken hands with "everybody" at a hospital - on the same day the advisors agreed handshakes should stop.
The Independent Scientific Pandemic Influenza Group on Behaviours, a subcommittee of SAGE, issued its advice on March 3.
It said: "There was agreement that Government should advise against greetings such as shaking hands and hugging, given existing evidence about the importance of hand hygiene.
"Promoting a replacement greeting or encouraging others to politely decline a proffered hand-shake may have benefit."
Yet on the same day, Boris Johnson said he had not stopped shaking hands.
He told the No10 press conference: "I was at a hospital the other night where I think a few there were actually coronavirus patients.
"And I shook hands with everybody, you'll be pleased to know, and I continue to shake hands."
Mr Johnson later said he'd stopped shaking hands - but only after shaking hands with Phillip Schofield and Anthony Joshua.
Downing Street said the PM “wouldn’t have seen” that specific paper on March 3 and may never have seen it. The document was only a submission to SAGE from its own subcommittee, not a report from SAGE to the government - which are kept secret.
3. The virus was spreading much faster than the scientists thought
SAGE admitted in late March that the 'R' number - the number of people each Covid-19 carrier infects - was higher than they first thought.
They had previously estimated it at 2.4, but on March 20 admitted "we cannot rule out it being higher than 3."
That meant it was spreading far faster than the government or the scientists had thought.
Chief Scientific Advisor Sir Patrick Vallance has since said the R number was 3 in the early stages.
4. Scientists lent support to a London-only lockdown - but it didn't happen
The week of March 15 was gripped by rumours of a "London lockdown".
These rumours were angrily denied at the time by Downing Street, which (correctly) said travel in and out of the capital would not be stopped.
But actually we now know "lockdown" doesn't mean banning all transport. And the documents show the rumours were much closer to the truth than Downing Street would have us believe.
SAGE held a discussion on March 17-18 about what it called - in its own words - a "London lockdown."
The scientists agreed shutting schools, bars, restaurants, theatres and offices would have the greatest effect on transmitting the virus.
And they made clear it could be London-only. The summary of the debate said: "Concerns were raised over whether locking down London would cause people travel and seed the virus in other places.
"It was confirmed that seeding in this way should not be a concern as infections are already present outside London."
But Boris Johnson decided not to do this. Instead he announced on March 20 that people should stop going to pubs, restaurants and bars UK-wide. A UK-wide lockdown followed on March 23.
Similarly, SAGE evidence on April 1 shows experts suggested regional pilots of lifting the lockdown. But the government is not following this approach. Instead the lockdown will be eased UK-wide - but could be reimposed locally if there's a spike in one area.
5. Scientists made the government change 'confusing' stay-at-home guidance
Scientists hit out at the government's "confusing" stay-at-home guidance before it was tightened up to herald the UK-wide lockdown.
Original advice - now withdrawn - said people should work from home "where possible" and "avoid non-essential use of public transport when possible".
But on March 22, SAGE scientists agreed that was not clear enough to stop people putting themselves at risk.
They wrote: "Phrases such as ‘as much as is practicable’, ‘non-essential’, ‘significantly limit’, and ‘gathering’ are open to wide differences in interpretation.
"This can lead to confusion about exactly what people are being required to do (e.g. gathering outside or going for walks). Guidance now needs to be reformulated to be behaviourally specific."
They also said the guidance must be combined with "hard-hitting emotional messaging" showing people the "personal threat" to their health.
6. The experts warn the lockdown must only be lifted 'very gradually'
More recent guidance from April 1 shows scientists agree the lockdown cannot be lifted in a hurry.
They say this isn't just because of the health benefits - if there's a second peak, it will undermine the entire public's trust in government advice.
The paper was drawn up by the scientific pandemic influenza group on behaviour (SPI-B).
It says: "If there is then an increase in infection rates that necessitates a reintroduction of restrictions this is likely to be seen as a serious failure of policy and trust in public health advice will be lost, leading to lower adherence to advice to restrict or to resume activity.
"To avoid these problems we would advocate trialling easing restrictions very gradually when epidemiologically indicated.
"While clearly explaining why these particular activities are being resumed and how risks must be controlled if these activities are to be maintained."
7. Lockdown must not just ease for work - leisure is important too
In the same meeting on April 1, scientists urged the government to let people return to leisure activities - not just work.
"To maintain public trust and support it will be important to have acceptable and equitable criteria for selecting which activities can be resumed," they agreed.
"For example, it may be difficult to justify easing restrictions solely for economic activities without any easing of restrictions for low risk activities with significant social and psychological benefit."
8. 'Immunity passports' could be hijacked by rogue employers - and put staff at risk
Rogue bosses could give riskier jobs to people who have had Covid-19 - thinking they're immune when they're not, the advisors say.
In a paper on April 13, the scientific pandemic influenza group on behaviour (SPI-B) said employers might "actively discriminate" against workers who were not shown to have antibodies.
The experts also say any 'immunity passports' - which have not yet been proven to work - could be hijacked by people trying to "game the system".
It's not yet been proven if having antibodies makes you immune to getting Covid-19 twice. And there is not yet a reliable antibody test available.
The government's advice warns even a 2% fail rate could lead to dozens of people in every thousand going back to work, or isolating, with the wrong advice.
The note added: "Some employers may discriminate on the basis of antibody status.
"This might include not permitting those testing antibody negative to return to work or only taking on new staff with antibody positive test results.
"Work may also be allocated among employees based on test status with, for example, customer-facing work being allocated to those who have tested antibody positive.
"In some circumstances this may be appropriate, but in others this might constitute adverse discrimination. This risk applies across all occupational sectors."
The note also warned about the risk of people trying to "game" the system by attempting to purchase a fake test result one way or the other.
9. And finally... 'herd immunity' was discussed
Some of the behavioural scientists suggested publicising the concept of "herd immunity" - to explain why the UK was not imposing social distancing measures in early March.
This is highly controversial because government has insisted "herd immunity" was never its plan.
Instead, they've more described it as a fact of life - the only way to permanently protect the population is through 'herd immunity', either by a vaccine or lots of people getting sick and recovering.
But this isn't government policy (so they insist) because it would lead to hundreds of thousands of deaths.
A paper dated March 4, considered by Sage on March 5, said: "SPI-B (scientific pandemic influenza group on behaviours) have divergent opinions on the impact of not applying widescale social isolation at the same time as recommending isolation to at-risk groups.
"One view is that explaining that members of the community are building some immunity will make this acceptable.
"Another view is that recommending isolation to only one section of society risks causing discontent."
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