The government will not launch any inquiry into who leaked a photograph of Matt Hancock kissing an aide, even though they believe they know who did it, the Guardian understands. Downing Street and Hancock’s Department of Health and Social Care (DHSC) have decided not to instigate any hunt to try to identify who passed the image taken from a security camera in his ministerial office to the Sun. The decision was taken at a meeting early on Friday morning involving Hancock, the DHSC’s permanent secretary, Sir Chris Wormald, and the department’s head of security, hours after the tabloid reported and provided evidence of Hancock’s encounter in his office on the ninth floor of the department with an aide, Gina Coladangelo. Sources say that they have ruled out a mole hunt because if the person were tracked down they could then claim that they were a whistleblower who was exposing wrongdoing. “Imagine if that person was dismissed for leaking what any employment tribunal that followed would be like for Matt Hancock,” said a source. “It’s hard to justify a leak inquiry when you’ve been caught brazenly doing something like this.” Another source familiar with the DHSC’s handling of the fallout from Hancock’s behaviour said: “They aren’t going to do a leak inquiry. The thinking is that you could argue that whoever did it was a whistleblower. If someone was whistleblowing, putting sensitive information into the public domain, they deserve to be protected – that’s good practice with whistleblowers.” The DHSC initially thought the photograph had been taken by someone using a long lens camera in a building opposite the DHSC’s headquarters on Victoria Street, a short walk from the Houses of Parliament. But it quickly discarded that theory and now believes that it came from a member of DHSC staff. The DHSC believes the picture is a photograph of an image captured by the closed-circuit television camera in Hancock’s office rather than a screengrab that has been taken from CCTV footage. However, it is bracing itself for the prospect of the Sun publishing further material, possibly including moving CCTV footage of Hancock with Coladangelo, who one source described as “Matt’s style guru, someone to spruce up his image, as much as someone who advises him on what to say and how to say it in media interviews”. Downing Street and the DHSC were asked if any leak inquiry would be held. A No 10 spokesperson said: “The prime minister’s spokesperson was asked about this at lobby [Friday’s briefing with journalists] and he said we don’t comment on security matters for obvious reasons, but he pointed journalists to DHSC for anything further on this matter.” Boris Johnson’s spokesperson declined at that briefing to say anything about an inquiry. The DHSC had not responded by the time of publication.