Boris Johnson has reportedly missed a key deadline in the COVID inquiry in which he was asked to hand over a phone and WhatsApp messages.

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 messages that were sent and received by Boris Johnson before May 2021.

Mr Johnson chose not to comply, as per the PA news agency.

According to PA, Mr Johnson's old phone - which contains the messages - is still in his and his team's possession while government officials and lawyers help him try to securely retrieve information from the device.

Mr Johnson was forced to change his mobile phone in 2021 after it emerged his number had been publicly available online for 15 years.

The BBC report that neither Mr Johnson nor his team can access the contents of his phone.

Access to any mobile phone conventionally requires a passcode - which only the phone's owner would normally know.

It has prompted Whitehall officials to formally explain to the inquiry why they have not yet been able to send them the correspondence.

BBC political editor Chris Mason says there is widespread irritation within the government at the failure to comply with the inquiry's demand to be sent Mr Johnson's messages.

Mr Johnson's team say "he will be happy to disclose any relevant material to the inquiry when it is accessible" and insist "full cooperation is underway".

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

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".

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.