The Government says it has hit its target for 100,000 coronavirus tests per day, with Health Secretary Matt Hancock saying it was an "incredible achievement".
Speaking at the daily Downing Street press briefing, Mr Hancock said 122,347 tests were performed in the 24 hours up to 9am on Friday, adding that testing would help "unlock" the UK's lockdown.
But questions have been raised over how the tests have been counted, with changes in the last few days meaning newer home test kits have been counted as they are dispatched.
The overall total also includes tests dispatched to "satellite testing locations" – such as hospitals that have a particularly urgent need – but does not detail whether the tests have actually been used.
When he set the target, Mr Hancock said the UK "will carry out" 100,000 tests every day by the end of April.
The Government's national testing co-ordinator, Professor John Newton, told reporters there had been "no change" to the methodology but said advice had been sought on counting as "new ways of delivering tests" were brought in.
He said: "There has been no change to the way that tests are counted.
"As we've developed new ways of delivering tests we've taken advice from officials as to how this should be counted.
"So, the tests that are within the control of the programme, which is the great majority, are counted when the tests are undertaken in our laboratories.
"But any test which goes outside the control of the programme, they're counted when they leave the programme, so that is the tests that are mailed out to people at home and the tests which go out in the satellite.
"So that is the way they are counted, have always been counted, and the way we were advised to count them by officials."
He said some 27,497 kits sent out to homes were included in the total alongside 12,872 tests delivered to satellite locations.
Guidance on the Government website appears to have changed on April 28 to include wording saying home tests and satellite tests were being included.
Shadow health secretary Jonathan Ashworth said: "Labour has repeatedly called for more testing, and increasing testing is an important milestone.
"But many would have expected the 100,000 promise to have been met by actually carrying out testing, not simply because 39,000 kits had been mailed out.
"The headline figure shouldn't count tests that hadn't been used, or indeed, might never be used as a completed test.
"Ministers promised transparency – the public and NHS staff deserve clarity."
Liberal Democrat acting co-leader Sir Ed Davey said: "The Health Secretary's arbitrary target of 100,000 tests by the end of April was always a hostage to fortune, and the truth is, he missed it.
"It's extremely disappointing the Government have decided to massage the metrics rather than admit they fell short, as this will only undermine public confidence."
It comes as 27,510 people have now died in hospitals, care homes and the wider community after testing positive for coronavirus in the UK as of 5pm on Thursday, up by 739 on the day before.
The death toll rose as:
– The Prime Minister is not expected to announce any changes to the lockdown measures before Thursday, the deadline to renew restrictions.
– Ryanair said up to 3,000 jobs could be lost at the airline, while unpaid leave and pay cuts of up to 20% are also proposed.
_ The head of the Royal College of GPs said half of consultations with patients could move online, while urgent cancer referrals have seen a 62% drop.
Mr Hancock said the next phase of dealing with Covid-19 – which will include more community testing and contact tracing – will allow the Government "to reassert, as much as is safely possible, the liberty of us all".
He told reporters: "In recent weeks we've had to impinge on historic liberties to protect our NHS and our loved ones and yet our goal must be freedom.
"Freedom from the virus, yes, and we will not lift measures until it is safe to do so.
"But also we care about the restoration of social freedom and economic freedom too – each citizen's right to do as they please."
But he said that, for now, people must stay at home while the number of cases of coronavirus is driven down further.
NHS medical director Professor Stephen Powis said officials will be studying whether stricter measures will or will not have to continue to apply to the elderly when the lockdown is eased.
"The over-70s can be absolutely fit and healthy, it's not the case that everybody over 70 has a chronic health condition or underlying disease," he said.
"As we look forward... I think it's a perfectly reasonable question to say how would that work in age groups and age bands?
"Although we do know that complications and unfortunately deaths are more common in the elderly even without complications, I think that's for consideration and that's work that we will need to do as we move forward."
Mr Hancock said 18,000 contact tracers to track those who have come into contact with an infected person will be in place by mid-May and the numbers will be expanded if necessary.
Asked whether parents would be fined for not sending their children to school when learning centres are re-opened, Mr Hancock vowed the Government would only allow pupils to return when it was safe to do so.
He said: "We are not going to re-open schools if it isn't safe.
"Of course, as and when we re-open schools, our goal is to get back to the norm and the position as it was before.
"I'm confident, because we'll only do it when it is safe, it will at that point be entirely reasonable and normal again to send your children to school."