Jenan Herzog Karagoli, Lady Beth's 21-year-old boyfriend, has admitted he was 'too gone' to save her

The boyfriend of an 18-year-old aristocrat who died after a two-day drugs and alcohol binge has revealed how her heartbroken father told him: ‘You could have taken better care of her.’

In an exclusive interview with The Mail on Sunday, Jenan Herzog Karagoli described how the Marquess of Queensberry confronted him after his youngest daughter, Lady Beth Douglas, was found dead in a squalid flat.

‘He told me that I could have looked after her better. I felt like her family were blaming me. There was a heavy sense of I could have done something,’ said Karagoli.

The 21-year-old also revealed how their relationship revolved around cocaine and that Beth – known as Ling Ling to friends and family – had a history of self-harm.

The tragedy emerged last week after an inquest heard how the teenager – a talented musician from one of Britain’s most distinguished aristocratic families – had been found unconscious with needle marks in her arm after taking cocaine and heroin.

Last night, Karagoli insisted he had done everything he could to save Beth after finding her unconscious at a house party in the early hours of March 7.

Lady Beth Douglas, 18, the youngest child of Lord David, the 12th Marquess of Queensbury, was found dead with needle marks in her arm

The couple, who had been together for ten months, had gone to the flat in Notting Hill, West London, close to the flat they shared with his mother in the iconic landmark Trellick Tower.

Karagoli described how he briefly left the party to buy a bottle of wine, but when he returned he found his girlfriend unconscious.

He said: ‘I saw her slumped on the sofa. I had a bottle of red wine in my hand and there was a guy next to us with a bottle of Hennessy.

‘I just crashed with her on the sofa. She seemed snug, so I joined her and fell asleep. I woke up at 1.30am and tried to wake her, and she was not waking up.

‘She was still warm, and that’s when I started to panic. I saw this man taking crack and he said that it happens all the time. I asked him, “What? What happens all the time? I don’t know what’s happened.”

The Marquess of Queensberry, with his Daughter Beth 'Ling Ling' (R) and his granddaughter Hero

‘I told him to call the ambulance, and I called an ambulance as well from her phone. Then I told him, “Here’s a tenner, get me some cigarettes.” That’s when he fled – he probably told other dealers to toss their phones.’

Karagoli added: ‘The ambulance took about 15 to 20 minutes. I was trying to put her in recovery. I was trying to resuscitate her, the paramedics tried to do CPR. They said she was deceased at the scene.’

Two weeks later, Beth was cremated in a Buddhist ceremony in London. Days afterwards, Karagoli was confronted by her father David Douglas, the 88-year-old 12th Marquess of Queensberry.

Karagoli insists that he did not know what was going on that night, but admits that his own drug-addled state may have affected how he could have helped Beth.

The squalid, now boarded-up flat in Notting Hill in west London, where Beth died at a party in March

He said: ‘David said I could have been a bit more conscious and taken care of her. I fully respect that – I hold nothing against that.

‘I fully believe I could have done more, but unfortunately at the time I was too gone.’

Karagoli also told The Mail on Sunday that Beth had recently set herself up as an online dominatrix using Twitter to advertise her services.

In the months leading up to her death, she posted a series of disturbing selfies and videos, including some of her half-naked. Others appear to show her under the influence of drugs.

She also offered to ‘perform naked’ on Skype for £20 and tried to sell her underwear. Most of the other posts are too explicit to be included in a family newspaper.

Both of the couple’s email addresses were posted publicly for clients to use when they were sending payments. Admitting he knew about the services, Karagoli said: ‘It was funny.

She would send people pictures, which was nice, and in reward [told them], “You are going to send me money.” She made about £500 from the whole thing. She ran it for two to three months.’

He denies that he personally took any of the money raised by her.

Talented musician Beth, 18, was known as Ling Ling to friends and family and had a history of self-harm

And he revealed that their relationship revolved around cocaine from the beginning, adding: ‘For the first few months, everything was flowery. We were taking cocaine and going to parties. We were taking cocaine not on a daily basis, but every other day.’

Last week’s inquest at Westminster Coroner’s Court heard that Beth had a history of drug and alcohol addiction, and had been known to mental health services since the age of 13 when she had begun self-harming. At 17, she was sectioned under the Mental Health Act.

At the hearing, the Marquess said he knew his daughter had a history of taking drugs but that he did not believe she had injected heroin before. He also criticised police for failing to identify the dealer who sold the lethal drug.

The inquest listed cardiac respiratory failure and cocaine and heroin poisoning as the cause of death. Coroner Dr Shirley Radcliffe said: ‘The police found no needles or syringes. As far as they are concerned there is no further action they can take.’

‘I wish I could have saved her’: Tragic teenage aristocrat’s niece HERO DOUGLAS pays tribute to ‘beautiful, bright and cool aunt’ who was ‘like a sister to her’

Ling Ling was my aunt but she felt more like a sister. We were born just eight months apart, were in the same school year, and both loved music beyond anything else.

She was incredibly beautiful, bright and always seemed very sophisticated to me (who was a bit of a country girl).

I loved it when I went to London to stay with grandpa (Ling Ling’s father) and got to hang out with her. She’d whisk me off to Covent Garden or Camden, and we’d eat noodles and buy trinkets from stalls.

She was great company and knew everything. I was like a sponge learning about what bands were cool, what was fashionable and what was not.

It feels inconceivable that she is no longer here, showing me the way. I am overwhelmed by grief and the knowledge that I’m leading the life that should be hers is almost too painful to bear.

How is it possible that I am at university and she is not? I would give it all up to have her back here with us.

I know my grandpa was an ‘older father’ but he was the most wonderful one and my mum always said it was lovely, as he had more time to be there for every swimming lesson, concert and parents’ evening. Ling Ling was absolutely loved, with two of the most devoted parents imaginable.

Hero remembers Beth (pictured) as a talented musician who joined the Royal Academy of Music’s Junior Department and gained grade eight distinctions in viola, violin and piano. Beth persuaded her parents to send her to the Purcell School of Music, but in the last years of her life she told her niece that she was no longer interested in music

She was my marker of what I should be achieving. I remember her reading the Harry Potter books and showing me a letter she had received from J. K. Rowling.

She excelled academically and went to Latymer, a selective grammar school where she was top of the class. She also joined the Royal Academy of Music’s Junior Department and gained grade eight distinctions in viola, violin and piano.

When I was 11, I went to Chetham’s School of Music, which was hard for Ling Ling as she was desperate to go to a specialist music school. Her parents were unsure because she showed such academic potential.

However, she was extremely persuasive and the following year she went to the Purcell School of Music.

Worryingly she’d recently become anorexic but it was managed well, and although everyone was concerned, I never thought that this was anything other than a blip.

I really wish I’d reached out to her more as she was showing a vulnerability that eventually led her into the wrong group of friends.

I remember that we were messaging each other after our maths GCSE. I was checking my answers and had clearly got one question completely wrong. But she was really gentle and sweet in reassuring me that everything would be all right.

It was uncanny how our lives mirrored each other as we’d both decided to leave music school and wanted to live at home again for the last few years before heading off to university.

She said something that really saddened me – ‘Music doesn’t interest me any more’ – and told me she was giving up. Music had been her whole life and I couldn’t understand why it no longer made her happy.

We had a falling out in the last year which led to her blocking me on social media. It was maybe inevitable because she was in a dark place but I wish more than anything that I’d been able to support her, or at least be there as a friend, when she needed me most.

Her mental health issues spiralled and she became unbearably unhappy and was sectioned for six months.

However, there is no consistency of care between child and adult services, and just a few weeks before she was 18 she was deemed OK and let out. Months later she was dead.

I am horrified that a girl who had never injected heroin before can die. No one trying heroin for the first time injects it themself – someone must have helped her. But the police don’t seem to care about finding out who that was.

The inquest recorded her cause of death as cardiac respiratory failure – her heart just gave up.

I try to remember her, not from this dark period, but as the wonderfully academically and musically brilliant girl that she was. I will always miss her.