Matt Hancock and his secret lover Gina Coladangelo attended Number 10's rule-breaking lockdown cheese and wine party - the same day he told the public to stay two metres apart.
The former health secretary is due to be questioned by senior civil servant Sue Gray, who is charged with investigating whether Government members breached Covid restrictions with a series of parties, in the coming days.
A picture of the gathering, held during the country's first national lockdown, shows the Prime Minister enjoying food and drinks along with his wife and 17 staff members in the garden at Downing Street.
The picture appears to show Mr Hancock and Ms Coladangelo were also in attendance, the Mirror reports.
The photo, first obtained by the Guardian, was said to have been taken on May 15 2020, during the first coronavirus lockdown.
Earlier that day Mr Hancock had told the public: "People can now spend time outdoors and exercise as often as you like - and you can meet one other person from outside your household in an outdoor, public place. But please keep two metres apart."
Ms Coladangelo, who has reportedly indicated she is happy to be questioned over the event, was working as an unpaid adviser to Mr Hancock at the time.
Mr Hancock, a married father-of-three, stepped down from his Cabinet role last summer after footage leaked from a CCTV camera inside his office showed him kissing and hugging married mum-of-three Ms Coladangelo, breaching his own coronavirus restrictions.
The Mail on Sunday reports a source close to Mr Hancock said the garden event took place "a long time before anything happened between" Mr Hancock and Ms Coladangelo, and that she had attended along with other advisers after debriefing the Prime Minister".
The source added: "It’s impossible to say with any certainty who the blurred figures in the photo are. What we can confirm is that Ms Coladangelo was an adviser to the Health Secretary at the time and part of the team that accompanied Mr Hancock to the Downing Street Press Conference that day.
"After the press conference finished at 5.53pm, Mr Hancock’s team went to the Downing Street garden to debrief the Prime Minister."
The source adds "there is no suggestion Ms Coladangelo or Mr Hancock did anything wrong", with the pair leaving at 6.32pm.
Downing Street has insisted it was a work meeting.
The Prime Minister's official spokesman said: "These were individuals in Downing Street - officials, staff - who were meeting after the most recent press conference that day, so meeting out of hours.
"There were meetings taking place both inside and outside No 10.
"This shows colleagues who were required to be in work meeting following a press conference to discuss work."
Deputy Prime Minister Dominic Raab muddied the waters by claiming staff were having a drink "after a long day" - rather than actively working.
Mr Raab told Times Radio: "Downing Street used that garden as a place of work. They used it for work meetings. The photo is from a day when, I think, the Prime Minister had just done a press conference.
"And sometimes they'll have a drink after a long day or a long week. And that's not against the regulations."
A source close to Mr Hancock said: “It's impossible to say with any certainty who the blurred figures in the photo are. What we can confirm is that Ms Coladangelo was an adviser to the Health Secretary at the time, and part of the team that accompanied Mr Hancock to the Downing Street Press Conference that day.
"After the press conference finished at 5.53pm, Mr Hancock's team went to the Downing Street garden to debrief the Prime Minister. Ms Coladangelo left with Mr Hancock and other members of his team at 6.32pm.
"There is no suggestion Ms Coladangelo or Mr Hancock did anything wrong, but both will obviously gladly help with any investigation. Ms Coladangelo - like the rest of Mr Hancock's team - was doing her job, helping vital public health communications in the teeth of a global pandemic.”
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