Bereaved families in Britain have warned they may take legal action against the Government over delays to starting the coronavirus public inquiry.
The Covid-19 Bereaved Families for Justice group is considering bringing a judicial review over the failure to provide a setting up date for the inquiry into the Government's handling of the pandemic.
They say this leaves the inquiry in "limbo", more than six months after Prime Minister Boris Johnson appointed Baroness Hallett to chair the probe in December 2021.
The PM has previously said the inquiry would start in spring 2022, but its terms of reference have not yet been published, nor a setting-up date specified.
The group says the delay could cost lives, as it slows down how quickly lessons can be learned, and is worried key evidence could be tampered with or destroyed.
Under the 2005 Inquiries Act, an inquiry "must not begin considering evidence before the setting up date".
Once an inquiry is under way it is an offence under the Act to destroy or tamper with evidence. The campaign group believes the six-month delay between appointing the inquiry chairwoman and giving a setting up date goes beyond the "reasonable time" allowed by law.
Elkan Abrahamson, head of major inquiries at Broudie Jackson Canter, who is representing the group, said taking legal action is the "last thing" families want but they may be left with no choice.
He said: "In the vast majority of inquiries a setting-up date is given within days or weeks of the chair being appointed, so this delay of over six months is both unprecedented and totally inexplicable.
"The consequences are extremely serious, as it only becomes a criminal offence to destroy or tamper with evidence after the inquiry's start date.
"By failing to give one, the Prime Minister is opening the door to key evidence being destroyed."
Jo Goodman, co-founder of Covid-19 Bereaved Families for Justice, said: "These delays slow down how quickly we can learn lessons from the pandemic and could cost lives, so why is the Prime Minister endlessly wasting time?
"He could set the inquiry up and get the process moving with the stroke of a pen.
"Even more worryingly, this delay makes it far more likely that key evidence will be lost or destroyed.
"If the Prime Minister can't do what's needed to let Baroness Hallett crack on with the job of learning the lessons from the deaths of our loved ones, we'll need to consider every option available to us."
A Government spokesperson said: "In accordance with the Inquiries Act, the Prime Minister has consulted the devolved administrations and is now finalising the terms of reference.
"These will be published shortly."