Boris Johnson will hand over messages from his old mobile phone that he had forgotten the passcode for to the UK Covid-19 Inquiry after technical experts managed to recover them.
The apparent breakthrough announced on Friday by a spokesperson for the former PM came after he was told to stop using the device over security concerns.
He then reportedly forgot the passcode.
But his spokesman said that the former prime minister was "pleased that technical experts have now successfully recovered all relevant messages from the device".
"As repeatedly stated, he will now deliver this material in unredacted form to the inquiry," he added in a statement.
"The inquiry process requires that a security check of this material is now made by the Cabinet Office.
"The timing of any further progress on delivery to the inquiry is therefore under the Cabinet Office’s control."
Mr Johnson was advised to stop using the phone and not access it again on security grounds while serving as prime minister in May 2021.
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It had emerged his number had been freely available online for 15 years.
The device he used during crucial periods of the coronavirus pandemic should contain messages relating to the ordering of three lockdowns in 2020.
An ally of Mr Johnson had conceded he did not have "100% confidence" he remembered the Pin, but the government found a version.
Furnishing the UK Covid-19 inquiry with the messages would be the latest development into the official investigation’s attempts to get to the bottom of the handling of the pandemic.
Ministers had battled to prevent the wholesale handing over of his notebooks, WhatsApp messages and diaries.
But the inquiry took the case to the High Court – and the government lost.
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