LONDON — Labour has called for text messages sent by Boris Johnson's wife about a potentially rule-breaking event in the Downing Street flat to be published.

The Sunday Times has reported there is evidence Carrie Johnson organized a gathering for the PM's 56th birthday in their flat, on June 19, 2020.

Labour deputy leader Angela Rayner demanded an investigation and urged Johnson to "come clean".

A No 10 spokesman failed to deny that a party had taken place.

A spokesperson for Carrie Johnson said senior civil servant Sue Gray had been aware of the text exchanges while carrying out her inquiry into Downing Street parties.

Boris and Carrie Johnson, as well as Chancellor Rishi Sunak, were fined by police last month for breaking COVID rules when they attended a brief 56th birthday celebration for the prime minister in Downing Street's Cabinet Room on the afternoon of June 19, 2020.

At the weekend, the Sunday Times reported that messages sent by Carrie Johnson suggested another event had taken place in the Downing Street flat that evening.

The newspaper said an aide had messaged Carrie Johnson at 6.15 p.m. to say the prime minister was on his way up to the flat — and that she had replied she was there with an unspecified number of male friends.

The Sunday Times also said Gray had been made aware of the texts but did not investigate the alleged event.

Responding to the claims, the government said the person who had informed Gray about the existence of the messages had not been willing to provide them to her inquiry.

Asked about the Sunday Times story, a No 10 spokesman said Gray had made clear that she would look at allegations where "credible" claims existed that the rules had been breached.

"Downing Street (staff) were given clear guidance to retain any relevant information and cooperate fully with the investigation," he added.

In a letter, Rayner has urged Cabinet Secretary Simon Case, the UK's most senior civil servant, to publish the relevant messages in his possession.

She also asked him to hand them over to the Privileges Committee, a group of MPs which is carrying out its own inquiry into whether the prime minister deliberately misled Parliament over Downing Street parties.

Rayner said Johnson must "come clean" about what happened.

"It appears that No 10 has now stopped denying that another lockdown-breaking secret gathering took place in the Downing Street flat," she said.

"Less than a week after the release of the Gray report, this raises serious questions about whether Downing Street has been caught lying yet again and why the event has not been investigated."

But Carrie Johnson's spokesperson told the BBC: "Sue Gray was aware of these [text] exchanges as part of her exhaustive inquiry into alleged breaches.

"Staff were given ample opportunity to present evidence including these messages and all relevant information was passed to the Metropolitan Police for investigation."

The publication of Gray's report — criticizing "failures of leadership" in No 10 — has increased the pressure on Johnson.

Meanwhile, the Cabinet Office has denied claims senior figures in government were able to edit or influence Gray's report before publication.

A spokesperson said it had been "impartially conducted and its contents represent the findings and conclusions of the investigation team alone". — BBC