Priti Patel has denied a claim by Dominic Cummings that the government’s original response to the coronavirus outbreak was to pursue a strategy of “herd immunity”.

In a series of tweets ahead of his appearance before MPs this week, Boris Johnson’s former top adviser said the policy was only dropped in March last year after a warning it would lead to a “catastrophe”.

Asked on the BBC’s Andrew Marr Show on Sunday morning about the claim that herd immunity had been the policy, Patel said: “Absolutely not.”

The home secretary added: “Our strategy was always about protecting public health, saving lives and protecting the NHS.

“Absolutely all colleagues involved in those meetings and discussions, working with the chief scientist and the chief medical officers, absolutely recognised that from the very difficult discussions that we had.

“At the time of a crisis when government is making very, very tough decisions, difficult decisions, we put public life and protecting the public at the forefront of all those decisions.”

Herd immunity was “never” put forward by the government at the start of the coronavirus pandemic, the chief executive of the UK Health Security Agency has also said.

Dr Jenny Harries told Marr: “I can categorically say I have never been in any Government meeting where herd immunity was put forward at that point of the pandemic as a mechanism of control.”

Cummings said that when the disease emerged in early 2020, the plan had been to develop resistance in the population in the months leading up to September.

In a series of tweets he said that it was only abandoned in early March after Downing Street was warned that it would lead to a “catastrophe”.

Cummings’ latest intervention comes as he prepares to give evidence on Wednesday to MPs on the Commons health and science committees who are investigating the government’s response to the pandemic.

Downing Street is braced for a potentially highly damaging onslaught following his acrimonious departure from No.10 at the end of last year.

In a foretaste of what to expect, he said that there may have been no need for any lockdowns if the country had had the “the right preparations and competent people in charge”.

Instead he said that at the beginning of March last year, the plan had been “herd immunity” and that claims to the contrary by health secretary Matt Hancock were “bullshit”.

He also strongly attacked the media for accepting the government’s denials.

“Media generally abysmal on Covid but even I’ve been surprised by one thing: how many hacks have parroted Hancock’s line that ‘herd immunity wasn’t the plan’ when ‘herd immunity by September’ was ‘literally the official plan in all documents/graphs/meetings’ until it was ditched,” he tweeted.

“Yes the media is often incompetent but something deeper is at work: much of SW1 (the Westminster postcode) was happy to believe Hancock’s bullshit that ‘it’s not the plan’ so they didn’t have to face the shocking truth. Most political hacks believe in ‘the system’…

“In week of March 9, No10 was made aware by various people that the official plan would lead to catastrophe. It was then replaced by Plan B. But how ‘herd immunity by September’ could have been the plan until that week is a fundamental issue in the whole disaster.”

At the time, the government’s chief scientific adviser, Sir Patrick Vallance, had said that if they tried to suppress the disease “very, very hard” it would simply bounce back when restrictions were released.

Instead he suggested the aim was to “build up some kind of herd immunity” so more people were resistant to the disease and transmission was reduced.

In his tweets, Cummings said there had been “so much lock down confusion”.

“Obviously they’re ‘destructive’. But if you have to do it because alternative is ‘hundreds of thousands choking to death and no NHS for months for everybody else and economy sunk because everybody hiding in terror’ then earlier/harder is better for health AND economy,” he said.

“If we’d had the right preparations and competent people in charge, we would probably have avoided lockdown 1, ‘definitely’ no need for lockdowns 2 and 3.

“Given the plan was AWOL/disaster and awful decisions delayed everything, lockdown 1 became necessary.”