The government had until 4pm on Monday to comply with a High Court ruling that ordered them to hand over the former prime minister's unredacted notebooks, diaries and WhatsApp messages from his time in Downing Street.

But according to the PA news agency, Mr Johnson's old phone - which contains the messages - is still in his possession while government officials help him try to securely retrieve information from the device.

He was told to stop using this phone while in office after it was discovered the number had been freely available for around 15 years.

It likely contains information and messages relating to the pandemic - specifically around the ordering of three national lockdowns in 2020.

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On Monday, Downing Street had said "all requisite material" had been given to the COVID inquiry after the government lost its bid to prevent their release.

The government had argued the request from inquiry chair Baroness Heather Hallett was "unambiguously irrelevant".

But the argument was dismissed by Lord Justice Dingemans and Mr Justice Garnham, who said while the order to provide material would produce "some irrelevant documents", it did not mean that power "cannot be lawfully exercised".

They also ruled that Lady Hallett should be able to examine the documents to decide if they are useful or not - and return those that are "obviously irrelevant".

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Mr Johnson told Lady Hallett last month that he would "like to" pass messages that are on the old phone to the inquiry.

He was believed to have written to the Cabinet Office at the time to ask whether security and technical support could be given to help access its contents without compromising security.

The PA news agency has approached Mr Johnson's team for a comment.