England’s chief medical officer has told the Covid-19 Inquiry he is “unsure” if shielding should be used as a measure to protect clinically vulnerable people in future pandemics.

Speaking at the probe in London on Thursday, Professor Sir Chris Whitty said shielding was both beneficial and harmful.

When questioned over the effectiveness of shielding, Prof Whitty said: “I think it was beneficial in one way, harming another way, and uncertain in a third.”

Asked if he would consider a similar approach in a future pandemic, he added: “There are two things I would definitely do. I think shielding, I’m unsure about, it would depend on the situation.

“I definitely think that the risk classification is really important because there are many other things that flow from them. And indeed, you don’t know what will flow from them always when you do it.

“And secondly, I do think it’s important to put in place a mechanism to support people who rationally have chosen to take themselves out of society, to better their ability to protect themselves.

“Whether the particular approach to shielding we took is an appropriate one to use, again, in respiratory infection, I honestly don’t know.”

Prof Whitty also criticised the Great Barrington Declaration as making “no medical sense”.

The open letter was published in the autumn of 2020 and argued lockdowns could be avoided by shielding the most vulnerable and allowing others to become infected in a bid to achieve herd immunity.

Prof Whitty said: “The Great Barrington Declaration approach, where you say you can shield the vulnerable and leave everyone else makes no medical sense, because shielding someone from a respiratory infection is extraordinarily difficult to do.

“People tried really, really hard here.

“Part of the logic of shielding was we knew that, inevitably, there would be infections at a higher rate in hospital and out of it, and part of the point was to ensure that people who are the greatest risk didn’t go into hospital at the point of the peak of the epidemic.”