Hugo Keith KC, the lead counsel to the inquiry, said the nation was "taken by surprise" by "significant aspects" of the disease, which has killed more than 226,000 people in the UK.

He told the inquiry the government was more concerned about an influenza pandemic, rather than one originating from a coronavirus, so it devoted more time and resources to it.

"The evidence may show simply, and terribly, that not enough people thought to ask because everybody started to assume it would be flu," he said.

While the UK may have been prepared for an outbreak of the flu, "it had not adequately foreseen and prepared for the need for mass testing in the event of a non-influenza pandemic".

Addressing the chair of the inquiry, Baroness Hallett, Mr Keith said: "You will hear evidence that for many years an influenza pandemic was assessed as being one of the most likely risks to the United Kingdom.

"But what about other risks? That whilst they might be less likely could be just as if not more deadly?"

Pete Weatherby KC, speaking on behalf of COVID Bereaved Families for Justice said the closest the UK had to a plan was the Department of Health's 2011 Pandemic Flu plan.

Kirsten Heaven, speaking on behalf of Welsh bereaved families, said the Welsh government also failed to plan for any other virus that had "pandemic potential".

"This was a catastrophic and unjustifiable failure," she said.

Claire Mitchell KC, speaking on behalf of COVID Bereaved Families for Justice Scotland added: "Despite a belief that the UK was a world leader in preparedness, it quickly and terrifyingly became clear we were not."

The UK, she said, "prepared for the wrong pandemic".

Meanwhile, Ronan Lavery, speaking on behalf of families from Northern Ireland, said the region was at least 18 months behind the rest of the UK in ensuring resilience to any pandemic flu outbreak.

Government 'crowded out' pandemic preparedness

The inquiry is split into several modules, with interim reports being produced at the end of each one.

This module looks at how prepared the UK was for the COVID pandemic.

Hugo Keith KC told the official inquiry that work around a possible no-deal exit from the European Union may have drained "the resources and capacity" that were needed for pandemic planning.

The Operation Yellowhammer document, which was published by the government in 2019, set out a series of "reasonable worst-case assumptions" about what would happen if the UK did not reach a deal with the EU.

It suggested there would be real risks of a rise in public disorder, higher food prices and reduced medical supplies.

But Neasa Murnaghan, speaking on behalf of the Department of Health Northern Ireland, said no-deal preparations may have actually been advantageous for her country's planning.

"Whilst these preparations did divert some of our focus away from pandemic preparedness planning, as was no doubt the case for all four nations of the United Kingdom, on the positive side the many aspects of additional training, improvements in the resilience of supply chains and the preparedness to manage the potential consequences were, when considered overall, advantageous," Ms Murnaghan said.

But she did admit managing the pandemic was "particularly difficult for a newly formed executive after three years with no government". The Stormont assembly was suspended from January 2017 until 11 January 2020, after power-sharing collapsed.

Families' 'dignified vigil'

The retired Court of Appeal judge began the first day of evidence of the official inquiry by welcoming the "dignified vigil" held by bereaved relatives outside the hearing.

Members of the COVID-19 Bereaved Families for Justice campaign group lined up outside holding pictures of loved ones as they expressed frustration at feeling "excluded from sharing key evidence".

Among them was Kim and her daughter Louise. They were emotional as they held a photo of their father and husband, Paul. In it, the smiling ambulance worker is warning his colleague to keep their distance from his baguette.

"He loved to make people laugh," said Louise. "If someone didn't find him funny, he would make it his mission to make them smile."

"I think that's what I miss the most," said Kim.

"Every day he would make me laugh.

"It has been three years but it is still such a wrench. We had so many plans."

They were standing outside the inquiry, they said, because they wanted Paul's story to be told.

"I wish it wouldn't shut us out," said Kim.

"I felt locked out when Paul was in hospital and I feel locked out now."