Around 30,000 deaths could have been prevented if the government had put the UK into just a week earlier, scientists have claimed.
Researchers used statistics to put together a model which they say shows that the death toll would be around the 8,000 mark - which is similar to Germany.
They also claim not only the lockdown could have been shorter but it would have caused less damage to the economy.
The model has been drawn up by British scientist James Annan from Blue Skies Research.
He wrote in a blog : "Implementing the lockdown one week earlier would have saved about 30,000 lives in the current wave (based on official numbers, which are themselves a substantial underestimate).
"It would also have made for a shorter, cheaper, less damaging lockdown in economic terms. And this is all quite simple maths that every single modeller involved in SAGE was fully aware of at the time."
His claims that an earlier lockdown would have saved lives has been backed by other researchers.
Dr Kit Yates, senior lecturer in mathematical biology at the University of Bath, told the Telegraph: "In the early stages of an epidemic, the number of cases is growing exponentially.
‘It is clear that, had we locked down sooner, we would have reduced the spread earlier, limiting the number of cases and consequently the number of deaths."
"The other benefit of locking down earlier would have been bringing cases under control sooner and potentially allowing the release of lockdown sooner."
As of Friday 36,393 people in the UK have died after testing positive for coronavirus.
Critics of Mr Annan's analogy say other factors may have contributed to the death such as the public not following early advice to stay at home before a stricter lockdown was introduced.
The news comes as the Prime Minister set a 10-day target to deliver a coronavirus test and trace system so the lockdown can be further eased across the country.
Mr Johnson said the government has recruited a 25,000-strong army of trackers to identify the contacts of infected victims and prevent further outbreaks of the killer bug.
The Government's scientific advisers had warned scheme must be up and running before restrictions could be lifted - including bringing back England's primary schools.
Mr Johnson told the Commons the tracing scheme was almost ready, despite problems with a government app that was meant to help the process.
He said: "We have growing confidence that we will have a test, track and trace operation that will be world-beating and yes, it will be in place by June 1."
