The families have issued a letter before claim, paving the way for judicial review of the prime minister’s failure to name a date for the inquiry which he has promised.
With Mr Johnson still saying only that a lessons-learned process will take place “in due course”, Labour stepped up pressure by setting a date for the first time for an independent inquiry to begin.
Shadow cabinet minister Rachel Reeves said public hearings should start in June a lockdown restrictions are lifted and continue through the summer.
The Covid-19 Bereaved Families for Justice campaign said the PM has refused to meet the families on six occasions over the course of the year.
Co-founder Jo Goodman, who lost her father Stuart, 72, to the virus, said: “With many of us approaching the anniversary of our loved ones’ passing, believe me we’d rather be with our families than standing in court. But if this government won’t listen and act, then that’s where they’ll be seeing us.
“The loss of our loved ones will not be in vain, the government must learn crucial lessons from this grim period if it’s to save lives now and in the event of future pandemics.
“PPE, care homes, lockdown timings, test and trace – there are so many questions that need answers. Only a proper inquiry can provide those answers: a statutory public inquiry that’s independent and led by a judge.
“The prime minister has promised an inquiry, but he seemed to miss it off his roadmap around reopening pubs.”
Ms Goodman added: “It’s staggering to us that the prime minister has refused to meet with our group of bereaved families six times and still refuses to start a critical inquiry to learn lessons that can save lives.
“The biggest responsibility for any government is protecting its own citizens, but it’s hard not to feel like Mr Johnson would rather protect his own image. The least the government can do is hear our plea and kickstart a statutory public inquiry, or else they can see us in court.”
Ms Reeves said that “justice is being denied” to bereaved families, who will not have closure until they better understand what happened.
She told The Guardian: “We’re supposed to be out of the roadmap by 21 June. Let’s get ready for it now, and from 21 June, this inquiry can really get started and use the summer months where we should be better protected, and the vaccine has been rolled out to most adults.”
She urged the government to work closely with bereaved families on the format for the inquiry.
“The inquiry is needed most of all by them,” said Ms Reeves. “So I think they should be in the driving seat really for how this is conducted, but it needs to be independent, it needs to be held in public. And it needs to be properly resourced,.”
Mr Johnson declined to set a date for the inquiry when quizzed in the House of Commons on Wednesday.
“I certainly take full responsibility for everything the government did, and of course we mourn the loss of every single coronavirus victim, and we sympathise deeply with their families and their loved ones,” said the prime minister.
“Am I sorry for what has happened to our country? Yes of course I am deeply, deeply sorry, and of course there will be a time for a full inquiry to enable us all to understand what we need to do better when we face these problems in the future, and that is something I think the whole House shares.”
England’s deputy chief medical officer Professor Jonathan Van-Tam said imminently launching a public inquiry into the government’s handling of coronavirus would be “an extra burden that wasn’t necessary” for medics and experts involved in the pandemic.
“I think the timing of inquiries is entirely a matter for ministers and politicians, it’s not a matter for physicians,” he told a Downing Street briefing on Wednesday.
“Personally, would an inquiry be an unwelcome distraction for me personally, at the moment, when I’m very focussed on the vaccine programme and the vaccine programme we might need in the autumn? Who knows? I think it would be an extra burden that wasn’t necessary.
“Is looking back on what you did and whether you could do things better a function of medicine, in terms of the clinical audit that happens in every GP surgery and every NHS trust up and down the land? Yes, it is.
“Will lessons be learned in due course? I am sure lessons will emerge.”