Ministers have been accused of spending taxpayers’ money on “loophole lawyers” in an attempt to block the Covid inquiry from being handed Boris Johnson’s unredacted WhatsApp messages.

Labour deputy leader Angela Rayner said the Government was “obstructing the Covid inquiry” after announcing a judicial review and questioned whether voters would consider the decision a good use of public money.

Does he think working people will thank him for spending hundreds of thousands of pounds of their money on loophole lawyers, just so the Government can obstruct the Covid inquiry?

The Cabinet Office has announced a High Court challenge of UK Covid-19 Inquiry chairwoman Baroness Hallett’s request for the wholesale handover of former prime minister Mr Johnson’s WhatsApp correspondence and notebooks from the pandemic.

The Cabinet Office says some of the information requested by the inquiry does not relate to the Government’s handling of coronavirus and is “unambiguously irrelevant”.

In a feisty exchange between Ms Rayner and Deputy Prime Minister Oliver Dowden in the Commons, Sir Keir Starmer’s deputy said: “They set up the inquiry to get to the truth, then blocked that inquiry from getting the information that it asked for, and now they’re taking it to court.

“Does he think working people will thank him for spending hundreds of thousands of pounds of their money on loophole lawyers, just so the Government can obstruct the Covid inquiry?”

Ms Rayner also raised the Conservative Party 2019 manifesto pledge to ensure the judicial review process is “not abused” or used to “create needless delays”.

“The Tory manifesto promised to end the abuse of the judicial review – how’s it going?” she asked.

Mr Dowden, who was standing in for Rishi Sunak at Prime Minister’s Questions due to the Conservative Party leader being in the US, said all Government Covid-related discussions would be handed to the inquiry.

He repeated the Cabinet Office’s assertion that some information in Mr Johnson’s WhatsApp conversations were “wholly and unambiguously irrelevant” and needed to be withheld.

The senior minister said: “We will provide the inquiry with each and every document related to Covid, including all internal discussions in any form as requested, while crucially protecting what is wholly and unambiguously irrelevant.

“Because essentially (Lady Hallett) is calling for years worth of documents and messages between named individuals to be in scope and that could cover anything from civil servants’ medical conditions to intimate details about their families.”

The decision to challenge the inquiry in the High Court is seen as highly unusual and one minister has raised doubts that the Government will win the contest, which could be heard before the end of the month.

At a preliminary inquiry hearing on Tuesday, Lady Hallett questioned why the Cabinet Office would want to redact information that Mr Johnson has confirmed he is happy to submit.

The retired senior judge has refused to back down from her request for Mr Johnson’s messages, saying it is for her to rule what is relevant to the investigation.

Health Secretary Steve Barclay joined in the defence of the Government’s position earlier on Wednesday, arguing that it was right to seek court instruction on the submission of WhatsApp messages as it was a “new area” in terms of the way Government business is carried out.

The Cabinet minister said it would be judges, rather than politicians, making the ruling on whether the chairwoman should see Mr Johnson’s unredacted correspondence.

“Wherever those boundaries are then set by the courts, then the Government will of course comply,” he told BBC Radio 4’s Today programme.

Mr Barclay said the Government’s trust in Lady Hallett was “not in question at all” despite the legal action, as he praised her as a product of the UK’s “world-leading” judiciary.

In a sign that the Government has not followed a unified policy when sharing information with the inquiry, Tuesday’s hearing heard how former health secretary Matt Hancock had passed on his WhatsApp messages unredacted but that the Foreign Office and Cabinet Office had edited out material submitted by senior aides.

Lady Hallett has given the Cabinet Office until the end of the week to clarify whether it would seek to redact information in Mr Johnson’s notebooks, his diaries and the WhatsApp messages on his locked mobile, containing messages dating from before May 2021, if they were obtainable before the judicial review is heard on or shortly after June 30.

The first public evidence session of the inquiry is due to start next week, with witnesses being called to give testimony from Tuesday about Module 1 of the investigation, which relates to the UK’s pandemic preparedness.