It is thought that the email sent between the health officials was about a Sunday Times article in May which criticised the delays in announcing a lockdown in March.
It was not until March 23 that the Prime Minister announced a nationwide lockdown.
A Government spokesperson said: “As recorded in the Sage minutes there was no disagreement on the substance of the scientific advice to ministers.
“This is a new virus and at every stage we have been guided by the advice of world-renowned scientists. There was no delay to lockdown. Sage advised on March 16 that further measures should be introduced as soon as possible.
“Our response ensured the NHS was not overwhelmed even at the virus’s peak, so that everyone was always able to get the best possible care.”
According to an investigation by the Sunday Times’s Insight team, Boris Johnson’s delay in imposing measures saw cases rise from 200,000 on March 14 to 1.5 million on March 23 as the Government deliberated on the timing and scale of the lockdown.
The study used backward modelling to calculate that the rate of infection was doubling every three days on March 14 – the date it is believed the Government first agreed that lockdown measures would be necessary to curb the virus’s spread.
Many of the drivers who died with Covid-19 had underlying health conditions and it is likely the frontline nature of their jobs added to their greater risk of death, the review by the UCL Institute of Health Equity found.
Figures show London bus drivers aged 20-64 had a mortality rate that was 3.5 times higher than men of the same age in all occupations in England and Wales from March to May.
It comes after ministers called for greater Parliamentary scrutiny over powers brought in to deal with the coronavirus outbreak.
The Commons Public Administration and Constitutional Affairs Committee (PACAC) issued two reports regarding the handling of the pandemic last week.
Committee chairman William Wragg said: “It is understandable that policy will need to be developed and implemented at pace, but it must equally be subject to robust and timely scrutiny.
“In the first six months of the pandemic, this has not been the case and this must improve.
“As we reach the six-month review of the Coronavirus Act, the Government should also provide greater opportunity for MPs to debate and express a view on individual aspects of the national response, not simply the act as a whole. If we are to maintain public consent in the restrictions, the ability of MPs to publicly debate the benefits and risks is critical.
“With the right leadership and clearly defined aims, a public inquiry can play an important role in learning lessons and driving improvements in the UK’s Covid-19 response.
“It will be important to establish an inquiry that seeks to learn from the challenges of the pandemic and provide recommendations on how to improve the co-ordination and policy principles that cover critical aspects of how Covid-19 has effected the UK. It will also need to be streamlined enough to make conclusions quickly, while provision is made to cover wider issues in further pieces of work.”
The committee said the public inquiry should aim to start taking evidence at the beginning of 2021.