The British government will investigate how images of former health minister Matt Hancock kissing an aide made it into the media, forcing his resignation.
After rejecting calls for Mr Hancock to be fired or to resign when pictures were published on Friday of him embracing a woman he appointed, Prime Minister Johnson accepted his decision to step down on Saturday.
The departure put renewed focus on the government over its handling of the Covid-19 pandemic.
Led by Mr Hancock, it stumbled in the early days over testing and protective equipment. Britain has one of the highest official coronavirus death tolls in the world.
A report by the BBC on Sunday that sensitive Ministry of Defence documents were found by a member of the public at a bus stop did little to dispel the sense of chaos within government. The ministry said it was investigating the incident.
Northern Ireland Minister Brandon Lewis said the Health Ministry would investigate how the images of Mr Hancock were taken in his government office and then leaked.
"It is a matter I know the department of health will be looking into to understand exactly how that recording ... got out of the system," Mr Lewis told Sky News.
He later told Times Radio there were two issues for the government to look into – whether the camera in Mr Hancock's office was there "appropriately" and, if it was there for security reasons, "how that video got out to the public domain".
The Sun newspaper published photos last week of Mr Hancock kissing the aide last month, at a time when coronavirus guidelines banned people from hugging others who were not members of their household. It also posted video footage.
After the images were published, many of Mr Hancock's Conservative colleagues privately called for him to go, saying his position was untenable after he admitted to breaking the coronavirus restrictions he had set.
Mr Johnson, who has dealt with various scandals including funding for the refurbishment of his apartment and a trip last year by his then senior adviser Dominic Cummings, who broke coronavirus restrictions, initially stood by Mr Hancock.
He then accepted the minister's resignation on Saturday and suggested Mr Hancock might return to a higher public role.
Britain's main opposition Labour Party raised questions about the Hancock scandal, including whether the former minister broke government rules.
"If anybody thinks that the resignation of Matt Hancock is the end of the issue, I think they're wrong," Labour leader Sir Keir Starmer said.
"The prime minister should have sacked him. Yet again Boris Johnson was too slow, too weak and didn't show the leadership that was needed.
"When the many people who made huge sacrifices during this pandemic see this, what they see is one rule for them and another rule for those close to government."
The Sunday Times, quoting documents, reported that Mr Hancock faced an investigation into allegations he had used his personal email to conduct government business, breaching guidelines.
"All DHSC ministers understand the rules around personal email usage and only conduct government business through their departmental email addresses," the Department of Health and Social Care said,
New Health Minister Sajid Javid, appointed by Mr Johnson on Saturday, said his top priority was the pandemic.
"We are still in a pandemic and I want to see that come to an end as soon as possible," said Mr Javid, a former chancellor of the exchequer.
"And that will be my most immediate priority, to see that we can return to normal as soon and as quickly as possible."
