Revealed Maker of Mone film worked as a private investigator on her behalf

For two consecutive Sundays, the PPE scandal involving the Conservative peer Michelle Mone has F made waves. First came the release of a YouTube documentary on 10 December about Mone, her husband, Douglas Barrowman, and PPE Medpro, a company they helped to win more than £200m in government contracts.

- David Conn, Russell Scott

Then came the BBC's heavily promoted interview with the couple, in which Mone admitted lying repeatedly to the public over her involvement in PPE Medpro and conceded she and her family were beneficiaries of an offshore trust that received a portion of its profits. The carefully managed media rollout is part of what Mone has called "our fightback".

It is a battle that has been aided by Mark Williams-Thomas, who investigated, produced, and presented the YouTube documentary, which was funded by PPE Medpro, and was sitting behind the couple when they were interviewed by the BBC's Laura Kuenssberg.

Williams-Thomas is a former police officer turned award-winning journalist who has a string of successful documentaries for ITV and Netflix. Amid questions last week over his independence in relation to the YouTube documentary, he said he had been "commissioned by PPE Medpro" to produce the film but retained "full editorial control". He said: "We have been totally upfront about who funded the programme and as to why we went down that route, putting in place safeguards to ensure editorial control and as much independence as possible."

What Williams-Thomas did not reveal publicly, however, is that, alongside his journalistic role, he has also been working as a private investigator on behalf of Mone, Barrowman and PPE Medpro.

In addition to trying to orchestrate a reputational comeback for the couple, William Thomas has been assisting his clients in their efforts to hunt for the suspected source of years of Guardian articles revealing that Mone and Barrowman had been lying to the public. Details of this side job have not been revealed by Williams-Thomas, perhaps because he has signed a non-disclosure agreement with his clients.