Sir John Bell has been giving evidence to MPs.
Speaking to the Commons Health and Social Care Select Committee yesterday, he said that a "central issue" to a lack of testing in hospitals was due to concerns over having to send staff home if they tested positive.
"As time went on, there still wasn't a real push to do healthcare workers and indeed, all patients in the hospital," Oxford University's Sir John Bell told MPs.
"And it sort of went on, and on, and on. And indeed there was a suspicion, which I think is probably correct, that NHS institutions and the NHS were avoiding testing their hospital workers because they were afraid they would find the kind of levels that Paul's described, and they would have to send everyone home, and as a result not have a workforce.
"That in my view is not an ethical approach to the problem. You can't not test people because you're worried about a human resources issue.
"But I think that was a pretty central issue in that failure to test hospitals."
The Oxford Professor also described one of the UK's biggest failures as not being on the "front foot" in preparation for a pandemic.
He told MPs: "The fact that we were asleep to the concept that we were going to have a pandemic, I think, shame on us.
"Since the year 2000 we've had eight close calls of emerging infectious diseases, any one of which could have swept the globe as a pandemic.
"This is not new and I think we should not be proud of the fact that we ended up with a system which had no resilience to pandemics. I think the biggest single failure was not being on the front foot.
"Singapore started the first week of January preparing for trouble, where it took us very much to the end of February beginning of March to get going.
"I think that's the single biggest failure and I think a lot of things fall out from that."
Professor Bell went on to praise the discovery of new therapies and the hunt for a vaccine at Oxford.
"But I think on another end of things, we've done really well in terms of evaluating new therapies," he told the Commons Committee.
"The Recovery trial has been fantastically good, the discovery of dexamethasone which cuts 35% of the mortality.
"We had some news yesterday which might actually end up that inhaled interferon is a useful therapy.
"You'll know the news about vaccines, I don't want to overhype the news about vaccines, but you know we're in the hunt for a vaccine, as much as anybody else is, which is a really pretty good result."
Professor Bell also said it was unlikely that Covid-19 will be eliminated.
"The reality is that this pathogen is here forever, it isn't going anywhere," he told MPs.
"Look at how much trouble they've had in eliminating, for example, polio, that eradication programme has been going on for 15 years and they're still not there.
"So this is going to come and go, and we're going to get winters where we get a lot of this virus back in action.
"The vaccine is unlikely to have a durable effect that'll last for a very long time, so we're going to have to have a continual cycle of vaccinations, and then more disease, and more vaccinations and more disease.
"So I think the idea that we're going to eliminate it across the population, that's just not realistic."
England's chief medical officer later launched a staunch defence of his actions over the Covid-19 pandemic, saying mass testing had to be abandoned due to capacity issues and lockdown came at about the right time.
In a heated exchange with former health secretary and chairman of the Health and Social Care Committee Jeremy Hunt, Professor Chris Whitty told MPs that widespread community testing earlier on in the pandemic required "an infrastructure we did not have".
Asked by Mr Hunt why he had not advised that testing be ramped up quickly in January or February, as had been done in "four weeks" recently, Prof Whitty said: "I respectfully differ.
"You are going to say I suspect at some point ... why is test, trace and isolate not brilliant now?
"This is after we've had huge investment and many months of preparation.
"The idea that you can suddenly switch this on, I'm afraid, is incorrect.
"The way you run emergencies badly is to try and run them based on a theory of what you could do rather than with the tools you have at your disposal.
"That is the way we had to run it and that is the way we did run it."
Professor Whitty told Mr Hunt that the Scientific Advisory Group for Emergencies (Sage) had consistently said that more testing capacity was needed.
But he agreed that, given the capacity, it was the correct advice to stop widespread community testing on March 12.
Whitty also said that ministers followed scientific advice with a "delay that was no more than you would reasonably expect".