Action should have been taken earlier to prevent the spread of Covid-19 at the start of the coronavirus pandemic, Sir Chris Whitty has told an inquiry.

England’s chief medical officer also denied warning ministers against lockdowns, describing how he had set out the downsides of locking down, but argued that was different to saying it should not happen.

Sir Chris was put under sometimes tense scrutiny by Hugo Keith KC, lead counsel to the UK Covid-19 inquiry, and was questioned following revelations from former chief scientific adviser Sir Patrick Vallance on Monday that he and Sir Chris did not always see eye-to-eye on the speed at which action was needed.

Sir Chris said he was “very aware” that there were two things that needed to be balanced – “the risk of going early (into lockdown or other similar measures), and the risk of going too late”.

He added: “My view is, with the benefit of hindsight, we went a bit too late on the first wave.”

Sir Chris said there was inevitable variation between what people thought when balancing all the issues.

He added: “And I was probably further towards, ‘let’s think through the disadvantages here before we act’ and also in making sure that in giving my advice that ministers were aware of both sides of the equation.”

Sir Chris said differences between himself Sir Patrick were actually “extremely small”.

Asked about claims in Sir Jeremy Farrar’s book about “friction or tension” between the top advisers in the early days of the pandemic, Sir Chris replied: “Well, Sir Jeremy, who is a good friend and colleague, had a book to sell, and that made it more exciting, I’m told.

“My own view was that actually the differences were extremely small.”

He said both he and Sir Patrick thought it was “appropriate” for Sir Chris to consider issues such as the impact of lockdowns on non-Covid illnesses and death as well as factors such as loneliness.

Sir Chris told the inquiry: “I did have a stronger concern, I would say than some, that the biggest impacts of everything we did – and I was confident we were going to have to do them to be clear.

“But when we started, the disadvantages of all the actions, not just for lockdown, but other actions before that, for example, what was initially called cocooning and then shielding as an example, and stopping schooling as another.

“The biggest impacts of those would be areas of deprivation and those in difficulties and those living alone and so on.

“So, I was very aware that we essentially had two different things we were trying to balance the risk of going too early, in which case you get all the damages from this with actually fairly minimal impact on the epidemic, and the risk of going too late, in which case you get all the problems of the pandemic running away.”

Mr Keith pressed Sir Chris on whether he was more cautious than others in wanting to see how Covid would unfold.

Sir Chris said: “I’ve rejected, and I will continue to reject, your characterisation of this as overreaction, because that implies that I thought that in a sense the action should not happen.

“What I thought should happen is that people should be aware that, without action, very serious things would occur but the downsides of those actions should be made transparent.

“I don’t consider that incorrect.”