Time is running out for UK ministries who are engaged in a bitter fight as they decide whether to take the astounding step of launching legal action against the Covid inquiry. The move is considered part of their battle to keep confidential a pile of sensitive messages from top UK figures, most notably Boris Johnson and Rishi Sunak.

With only 48 hours until the deadline for handing over unredacted texts and notes between Johnson and his ministers, the Observer reported that the government is sticking hard this weekend in its reluctance to provide the data.

According to legal experts, it only has a few days to file a legal challenge against Heather Hallett, the former court of appeal judge and chair of the probe. It is worth noting that Hallett has cautioned that refusal to obey her order is a criminal offense punishable by a fine or jail.

With the first public hearings just over two weeks away, the debacle is seen as crucial in framing the probe. It is expected that key Conservatives from the previous 13 years of administration, including David Cameron and George Osborne, will be interrogated about the actions they took to prepare for a pandemic, as well as the impact of austerity on the NHS' resilience. The inquiry's lawyers have revealed that they have cast their net "widely and with a fine mesh."

With the battle between the inquiry and the Cabinet Office raging for weeks behind closed doors, it only now emerged that the inquiry used its significant legal powers, as per section 21 of the Inquiries Act 2005, to demand unredacted documents. On its part, the Cabinet Office refused, claiming only “unambiguously irrelevant” material had been removed and that the inquiry’s demands were unlawful.

Pursuing the argument that the inquiry does not have the power to compel it to hand over the unredacted relevant material, the Office's legal team claims that disclosing the information will stymie future policy talks and establish a bad precedent in reference to the Human Rights Act and data protection legislation.

Senior experts, though, are already warning that any challenge is unlikely to succeed. "They've either got to hand over the material, or they've got to bring judicial review proceedings on the basis that her request is unreasonable," former Tory attorney general Dominic Grieve said.

"I think it is likely they will be given pretty short shrift if they turn up at court to argue that; Seeing that Heather Hallett is cleared to a very high level of security, why should it matter that she sees the entirety of [the material]? She will decide what is relevant,” Grieve added.

Charles Falconer, the former Labour lord chancellor, said as quoted by the Observer he maintained Lady Hallett would “unquestionably” win.

“It’s completely wrong that the Cabinet Office – the heart of government – is trying to prevent the chair of the Covid inquiry from seeing the material,” he said. “She is very highly respected. She would not have insisted unless she thought she needed this material. [The government] should respect her and her inquiry and not stand in her way,” he added.

Hallett's decision covers correspondence between more than 40 of Johnson's most senior officials. It contains Johnson's WhatsApp conversations, diaries, and notebooks, as well as emails from former No. 10 adviser Dominic Cummings, Liz Truss, Dominic Raab, who was deputy Prime Minister at the time, Matt Hancock, the then-health secretary, and cabinet secretary Simon Case.

In his capacity as chancellor during the pandemic, Sunak is set to stand out. His correspondence will be considered carefully in what concerns the “eat out to help out” scheme. At the time, some experts feared it would help COVID to spread.

In what concerns the ongoing battle, Hallett delivered a judgment dismissing the protests, noting that it was up to the investigation to determine what was important. In an alarming development, Hallett stated that she had seen material concerning talks between Johnson and his advisors about the Metropolitan Police's enforcement of COVID restrictions in the aftermath of Sarah Everard's death. She stated that the material was previously withheld.

Cabinet Office spokesperson said, “We are fully committed to our obligations to the Covid-19 inquiry. As such, extensive time and effort have gone into assisting the inquiry over the last 11 months. We will continue to provide all relevant material, in line with the law, ahead of proceedings getting underway.”

A spokesman for Johnson said, “We have and will continue to disclose all relevant material to the inquiry.”

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