It is the intensely humiliating photograph that sealed the downfall of former cabinet minister Peter Mandelson.

Standing in a pair of white Y-fronts and talking to a young woman wearing a dressing gown, Labour’s so-called ‘Prince of Darkness’ appeared at home in paedophile Jeffrey Epstein’s palatial mansion in Paris.

Now the woman in that extraordinary picture – a former Russian model who was one of Epstein’s many victims – has broken her silence in an exclusive interview with The Mail on Sunday.

Mia, whose name has been changed to protect her identity, revealed the image was taken surreptitiously by Epstein as he sat behind his desk in a room in his substantial apartment she knew as ‘the library’.

She believes the picture – found amid the Epstein Files – was part of the paedophile financier’s secret bid to collect images of powerful guests in compromising positions.

Mia thinks the photograph was taken around 2010 when she was in her mid-20s. She recalled: ‘I don’t remember [Mandelson] walking around like that often. Possibly he could have been getting a massage. 

‘There was a masseuse who came quite often. I think she was from Lithuania.

‘Honestly, I don’t remember what we were looking at, [it seems] as if he was showing me something, some gadget.’

Mia, the woman in the photograph and whose name has been changed to protect her identity, revealed the image was taken surreptitiously by Epstein as he sat behind his desk

She believes the picture – found amid the Epstein Files – was part of the paedophile financier’s secret bid to collect images of powerful guests in compromising positions 

She said she was ’99 per cent certain’ Epstein took the photograph because the angle suggests it was snapped from his desk, given the layout of the room.

‘He loved taking provocative photos where people looked far from their best,’ she said. 

‘The photo is disgusting. [Mandleson] is not the most pleasant person in the world anyway, and in his underpants… aside from grimacing, [the picture] evokes no other emotions.’

Commenting on the appropriateness of Mandelson quizzing her while standing in his underwear, she added: ‘It’s utter trash.’

Mandelson – sacked as Britain’s Ambassador to the US in September after his full links to Epstein were exposed, raising questions about Sir Keir Starmer’s judgment in appointing him – has denied any knowledge of the financier’s crimes ‘because of the lies he told me’. 

The 72-year-old was last month arrested on suspicion of misconduct in public office.

Mia was part of Epstein’s retinue for several years. He housed her in one of his Manhattan apartments and controlled every aspect of her life, she claimed. 

She also met Andrew Mountbatten-Windsor when he visited Epstein in December 2010.

She described Mandelson as ‘unfriendly’, ‘sullen’ and ‘very unwelcoming’ and accused him of treating young women in Epstein’s orbit – many of whom are now known to be victims – with disdain.

‘Peter was like a freeloader, moving from place to place, staying on yachts, in Paris, in houses,’ she told the MoS. 

‘He just seemed like some high-profile guest who was so important that there was no need for him to talk to us, the staff, no need for him to be pleasant.’

She described Mandelson’s attitude towards the women in Epstein’s homes as ‘arrogance’, adding: ‘It was looking down on us. I don’t even remember whether he knew my name.’

Mandelson was less aloof with Mia on a later visit to New York, she recalls, when Epstein ordered her to act as his personal shopper.

The MoS revealed earlier this month how Epstein arranged for the politician to have Botox injections while he was on a taxpayer-funded visit to Manhattan in March 2010, while the financier was still under house arrest.

Epstein controlled every aspect of the lives of the young women ensnared in his sex-trafficking web. 

At one point he ordered Mia – who has received a payout from a fund for victims – to have her hair cut, telling her ‘you’re too old to have long hair’. 

‘He controlled our clothing, hair, teeth, sport, exercising, everything,’ she said. 

‘No one had medical insurance. If you needed to see a doctor, you had to ask his permission, and he sent you to his doctors.’

When he visited Paris, Epstein still kept New York time and went to bed late. He expected the girls in his retinue to act on his instructions at any time. 

‘So maybe that photo [with Mandelson] was taken in the morning, before I’d had time to get dressed,’ she said.

Mia described how Epstein was a supreme manipulator. ‘He seemed to see right through you, understand your vulnerability, then become the only person who could solve your problem,’ she said.

‘Then gradually, step by step, he would crush you. He drew people into this web. Even very powerful people got caught.’

Mandelson did not respond to a request to comment last night.