Boris Johnson unredacted WhatsApps will be inspected by the Covid Inquiry team this week - despite a messy legal fight with Rishi Sunak's Government.
Side-stepping the Cabinet Office, the Inquiry's legal team said it would take the ex-PM up on his offer to examine documents requested by the probe.
It comes after the Government failed to produce the documents last week and instead launched a legal fight attempting to block the release.
Counsel for the Inquiry Hugo Keith KC said: "The inquiry team has been liaising with his [Mr Johnson's] legal team to arrange for the inspection of the unredacted WhatsApps that he had provided to the Cabinet Office, which he had returned to him.
"We expect to begin that inspection this week.
"The inspection will allow your team to make its own assessment as to the redactions applied by the Cabinet Office and to satisfy ourselves and ultimately you of their appropriateness or otherwise."
He added that Mr Johnson's locked former phone had been handed to the Government with the hope of obtaining his WhatsApp messages from pre-May 2021.
He told the Inquiry: "Mr Johnson also holds an old phone that was turned off in 2021 for security reasons.
"Neither Mr Johnson nor the inquiry has the technical expertise to ensure the contents of the phone can be downloaded safely and properly, particularly bearing in mind the overarching need to ensure no damage is done to national security.
"We have therefore agreed that this phone should be provided to the appropriate personnel in government for its contents to be downloaded.
"We have asked the Cabinet Office, in liaison with Mr Johnson and those government personnel, to obtain the phone without delay, to confirm in writing the process by which it will be examined and to give confirmation that it, like the diaries and the notebooks and the WhatsApps, will be accessed fully.
"That is to say, there will be no redactions made to the contents, other than in relation to national security, before we may view it."
It came as the chairwoman remained tight-lipped on the ongoing legal battle with Mr Sunak's Government over the disclosure.
But she reiterated her view, saying: "As has been widely reported in the media, an issue has arisen between the inquiry and the Cabinet Office as to who decides what is relevant or potentially relevant.
"I issued a notice under Section 21 of the Inquiries Act 2005 making it clear that, in my view, it is for the inquiry chair to decide what is relevant or potentially relevant.
"The Cabinet Office disagrees, claiming they are not obliged to disclose what they consider to be unambiguously irrelevant material. They invited me to withdraw the Section 21 notice. I declined.
"They are now challenging my decision to decline to withdraw the notice in the High Court by way of judicial review.
"With litigation pending and as the decision-maker, I can make no further comment."
As the row rages on over the release, the Inquiry revealed ex-Health Secretary Matt Hancock's WhatsApps - previously leaked to the press - have been submitted.
The KQ representing the Inquiry also revealed evidence has been summoned from Rishi Sunak, ex-PMs Liz Truss and Boris Johnson, and senior ministers during the crisis including Dominic Raab and Michael Gove.
The demands relate to module 2 of the Inquiry probing the UK's decision making and political governance during the pandemic.
