Inside the mind of serial killer Dennis Nilsen, by the man who knew him best

When the police interviewed the 37-year-old Dennis Nilsen in February 1983, after discovering dismembered body parts in his north London flat, what shocked them the most was his matter-of-fact demeanour.

Behaving more like a disinterested witness to his crimes than the perpetrator of them, Nilsen calmly told his interrogators that they would find further human remains stowed in a tea chest in his living room and inside an upturned drawer in his bathroom. Much in the manner of a man reciting a shopping list, he went on to enumerate the murders he had committed, nonchalantly describing how he had buried the bodies of his victims under the floorboards, then dug them up, and sat them beside him to watch TV, how some he had burnt on a bonfire in his back garden, and others he had chopped into pieces and flushed down the lavatory.

At length, Nilsen’s dumbfounded solicitor, Ronald Moss, interrupted to ask the question. ‘Why?’ ‘I am hoping,’ Nilsen replied, ‘you will tell me that.’

Nilsen is Britain’s second-worst serial killer (Harold Shipman is the most prolific). Between 1978 and 1983, by his own admission, Nilsen murdered 15 young men, most of them rootless drifters, drawn to London because of the unemployment crisis, whom he would pick up in pubs, before taking them back to his flat and strangling them. It was the anonymous lives that most of his victims led that enabled Nilsen to kill for as long as he did without detection; only seven of his victims were ultimately identified.

As a new three-part ITV drama, Des (as he called himself) demonstrates, Nilsen was a very unusual serial killer. Starring David Tennant as Nilsen, the series eschews what might have been the obvious route of depicting his crimes in full, gory detail. Instead it follows the police investigation from the time of his arrest, and examines Nilsen’s relationship with Brian Masters (played by Jason Watkins), the author of the book, Killing For Company, on which the series is based, and the man who over a period of 10 years came to know Nilsen better than anybody else. ‘Yes,’ Masters, who is now 81, with a mind like a razor, tents his fingers and ponders on this, ‘that was not my intention, not what I was looking for. But it happened.’

Masters has had a light hand in the production. He visited the set once, and entertained Watkins for lunch at the Garrick Club to discuss his role. But when I spoke to him he had not even seen the programme. He was sent a link to watch it, he says, but couldn’t work out how to download it on his computer.

At the time he first met Nilsen, in Brixton Prison, where he was on remand, Masters was not the obvious candidate to become a murderer’s confidant. He was the author of books on Molière, Albert Camus and a history of the noble families of Europe, a member of the Garrick and a friend of Zsa Zsa Gabor, whose photograph stands on the desk in his study in the west London home where he has lived for 54 years.

Like everybody else, he had read of Nilsen’s arrest in the newspapers. But what drew him to the case was not the gruesomeness of the crimes, but the psychology of a man who could commit them. ‘I thought, this is deeply interesting, for all the right reasons. Not the wrong ones.’

Masters is gay. ‘When I read about all the victims being male… and in those days nobody spoke openly about these things, I thought, “My goodness, somebody is going to write about this, but it mustn’t be somebody who doesn’t know what he’s talking about.” I could at least understand what it’s like to live like that. I thought that somebody who is responsible ought to deal with it. Maybe it’s me.’

He wrote to Nilsen in prison, outlining his desire to write a book. Nilsen replied: ‘Dear Mr Masters, I pass the burden of my life on to your shoulders’ – a phrase Masters recalls with a visible shudder. Three weeks later, he met Nilsen for the first time. ‘We were at a table, he’s on one side, I’m opposite. There’s an ashtray on the table – a tin – and a guard in the corner.’

As we talk, Masters walks to a hard-backed chair, which he sits down on, arm resting on the back, assuming a posture of arrogant selfassurance. ‘Nilsen sat on his chair like that – in other words, “OK, get on with it, I’m in control.” That was his body language. He worked in a Jobcentre; his professional life was to size people up, and see if they were good for the job.’

So he felt Nilsen was trying to manipulate him? ‘Oh yes, at the beginning.’ Masters chuckles to himself. ‘He was so cocksure of himself he didn’t recognise until it was too late that it wasn’t him in control. It was me.’

And so it began. Letters, visits, Nilsen besieging Masters with 52 exercise books, each of 50 pages ‘every line filled to the edge’, with details of his life and crimes. ‘He told me everything.

Nilsen was born in 1945 in Fraserburgh, Aberdeenshire. His father was a Norwegian soldier, part of the Free Norwegian Forces, who had arrived in Scotland following the German occupation of Norway. But Nilsen’s parents divorced when he was three, and he never saw his father again. Nilsen, his mother, brother and sister lived with his grandparents, and his grandfather, a fisherman, became the central figure in his life. He died at sea when Nilsen was six. He would later describe seeing his grandfather lying in his coffin as ‘the most traumatic event of my life’.

Nilsen had realised he was gay at the onset of puberty. A solitary boy, he found it hard to make friends. At the age of 16 he enlisted in the Army Catering Corps, going on to train as a chef – and a butcher – eventually leaving the service after 11 years. He moved to London and enlisted as a trainee police officer. But it was barely a year later, before he had completed his training, that he left the force and started work in a Jobcentre in Soho.

Nilsen was a diligent worker; he was also an outspoken, and sometimes obstreperous, trade-union representative. His evenings were spent in gay pubs – his secret life – sometimes picking up young men for casual encounters.

In 1975 outside a pub on the Bayswater Road, he met a blond 21-year-old named David Gallichan, whom he nicknamed ‘Twinkle’. They set up home in a flat in Melrose Avenue, Cricklewood. The relationship lasted a year; the longest Nilsen had ever had, and when Gallichan walked out, Nilsen’s life fell into a pattern of work and drunken depression.

According to Nilsen, on 30 December 1978 he had been drinking alone all day when he decided that he must ‘at all costs’ leave his flat and find company. In a local pub he picked up a boy who was trying unsuccessfully to buy alcohol. Stephen Holmes was just 14, although Nilsen would later claim to have thought he was older. He invited Holmes home, where after a bout of heavy drinking they both fell asleep. The next morning, Nilsen awoke to find Holmes beside him. ‘I was afraid to wake him in case he left me,’ he wrote later.

With a necktie, he strangled Holmes until he was unconscious, then drowned him in a bucket of water. ‘It was the beginning of the end of my life as I had known it,’ he wrote. ‘I had started down the avenue of death and possession of a new kind of flatmate.’

Nilsen abused Holmes’s body, then buried it under his floorboards where it remained for eight months before he disinterred it and burnt it on a bonfire in his back garden. It would be some years before Holmes was even identified.

His next victim, in December 1979, was a 23-year-old Canadian student named Kenneth Ockenden, whom he picked up in a pub, taking him home and strangling him with the cable of his headphones as he listened to music. Again, he buried the body under the floorboards, periodically retrieving it over the next two weeks, washing it and sitting it in a chair as he watched TV, before putting it back under the floorboards – according to Nilsen saying, ‘Goodnight, Ken.’

For Nilsen, it was as if love, abandonment and death were inseparably fused in the passing of his grandfather. Even before the killings, he would fantasise about his own death, whitening his face and posing in the mirror, imagining himself as a corpse.

At one point in my conversation with Masters, I read him Nilsen’s account of one anonymous victim. ‘I would hold him close often, and think that he had never been so appreciated in his life before… After a week I stuck him under the floor.’

‘Stop!’ Masters almost shouts. ‘He’s talking about himself. It’s diversion of subject. He is putting himself in that person’s place. He wants to be that person. His grandfather drowned. And he was always identifying with that exit from life – and with a time he had been cared for and looked after.’

Between 1978 and September 1981, Nilsen killed a total of 12 men. But in October 1981 he was forced to leave his flat after his landlord told him he wanted to renovate. He moved to an attic flat in Cranley Gardens, Muswell Hill.

‘There’s one very revealing remark in his diaries,’ Masters goes on. ‘When he moved, he went from a ground-floor flat, which had a garden and floorboards, beneath which he could put people, to an attic flat. And he said he was elated that day – “nothing can go wrong now. It must be over. I can’t do anything here.” That first night he went out and chatted somebody up and took him back for a drink, and everything was all right. The person went home. Normality was what he wanted.’

But it was not to last. Over the next 16 months Nilsen would kill three more men. He was finally discovered in February 1983, after a plumber was called to investigate smells coming from the drains outside, and discovered human body parts.

‘Somebody wrote a letter to the landlords about the drains, saying this is an intolerable situation; it’s unhealthy,’ Masters says. ‘I went to the landlords and found the letter, and it was Nilsen’s handwriting. He wanted to be caught.’ Masters says he felt no apprehension about striking up a relationship with Nilsen. Their meetings in Brixton Prison were, as he puts it, ‘secure, to say the least, and I already realised that an addictive killer would not be able to turn his addiction on at will’.

It was his friends who grew concerned for Masters’ state of mind, as the meetings with Nilsen progressed. ‘They would press me to tell them what he was like and how did he refer to his crimes, what he did, and how did he feel doing it? Predictably, some people were turned off their food. For myself, the endeavour was always professional, never a satisfaction of gruesome interest. I was engaged on a search for psychological truth, not awe and shock.’ So, the question persists, why did Nilsen do it? The psychiatrist will tell you it’s down to ‘a personality disorder’, Masters says, ‘which of course tells you nothing.’ The brain surgeon will tell you there was a chemical imbalance in the brain. ‘But again, that doesn’t tell you what changed the balance.

But there’s one man who does know, and that’s the priest. He says it’s something called Satan, and he takes over and you can’t resist his malign influence except through an effort of will. And Nilsen more or less corroborated that view.

‘He would never use the word “possessed”, but he used words we would use in our everyday language: “I don’t know what came over me... what got into me.” It was like Jekyll and Hyde syndrome, as if it happened to somebody else who inhabited his body for short periods.

‘And he said that when he was in the grip of a murderous phase, he was astonished at how strong he was. He said it takes about 20 minutes to squeeze the life out of somebody – it’s not easy; he didn’t realise he could do it.’

Reading Nilsen’s confessions, it wasn’t the killings that Masters found so disturbing; it was the desecration that Nilsen visited on the dead bodies of his victims.

‘I once remonstrated with him, “Look, I do understand that it’s possible to kill people, but what I don’t understand is how you could cut up a corpse; then make yourself a cup of coffee, butter a slice of toast and eat it.” ‘He said, “Well, there’s something wrong with you.” I said, “What do you mean?”

He said, “Afterwards, a corpse is a thing – it can’t feel; it can’t suffer. If you’re more upset by what I did to a corpse than what I did to a living person, then your morals are upside down.”

‘I had to take a deep breath, because logically he was right; but thank goodness human beings are a bit more than just logic.’

Masters continued to visit Nilsen in prison for 10 years after his conviction. It was, he says, a moral duty.

‘This man had given me 52 exercise books of his personal, private and revolting reminiscences. I used it as one of my main literary sources for the book I wrote. Should I now turn around and say, “Thanks for all your help, I couldn’t have done it without your cooperation, now you can rot?” I couldn’t do it.’

The visits finally came to an end when Masters, speaking on the radio, compared Nilsen’s crimes to those of the American serial killer Jeffrey Dahmer – about whom Masters also wrote a book. ‘He didn’t like that at all.’ The requests from Nilsen for visits suddenly stopped.

Did Masters feel compassion for him? ‘No. I felt a sense of compassion for the person who’d been smothered inside him – there was a little boy in there somewhere. I think he recognised that he was missing something in his moral fibre. I do believe he regretted it all, but I don’t believe he was capable of remorse. He knew that what he’d done was against the law and he must be punished for it, but he didn’t understand why it mattered. “What’s the fuss about?” That’s so important, because it separates fact from feeling.’

When the time came for Nilsen’s trial in October 1983, everybody expected him to plead guilty. But at the last minute he changed his plea to not guilty, because of diminished responsibility.

Masters travelled to Scotland to visit Nilsen’s mother. ‘Betty,’ he says. ‘A sweet, little white-haired lady. I knew all the evidence would be read out in court, and I couldn’t let her see it in the morning papers. She made me very welcome, cooked a nice dinner and she started to tell me things about Dennis’s childhood, how he used to look after sparrows with broken wings and so on. And I said, “Betty, I’m sorry but I’ve got to tell you this.” “Och,” she said, “I blame London.” Later she said, “I hope he did it in a nice way.” I said, “You can’t do things like that in a nice way.”’

Betty had three children by Nilsen’s father, and another five by her second husband. ‘She said, “Dennis was the only one I could never cuddle.” She felt a repulsion. What I wanted to say to her was, “Betty, if you couldn’t cuddle him, it’s not his fault. It’s yours.” But I couldn’t say it.’

In October 1983, Nilsen was convicted on six counts of murder and two of attempted murder, and jailed for life. In 2018 he died from pulmonary embolism in hospital in York, having been taken there from prison.

It is one of the imponderables of the Nilsen case that a number of his pickups were able to leave safely. Then there were the three men he did attempt to kill but who were able to escape. One was Carl Stottor.

I met Stottor in 1993, nine years after his encounter with Nilsen. He told me that he had come from a broken home and at 15 come out as gay. At 17 he was working as a part-time model and go-go dancer in Blackpool, ‘like a Hot Gossip-type thing, only we wore a lot less’.

He had fallen into a relationship with an older, violent man, then ran away to London. On his first night in the capital he went to The Black Cap, a gay pub in Camden High Street. A man sat down beside him and introduced himself as Des. ‘I thought,’ Stottor said, ‘that he was pretty genuine – but then I’m a real judge of character, aren’t I?’

The details were punctiliously rendered: how they had held hands in the taxi back to Cranley Gardens; the dingy flat; the two Bacardis; Nilsen’s dog, Bleep; the music he was listening to on Nilsen’s headphones (O Superman by Laurie Anderson). They went to bed. There was ‘a little bit of physical contact, not much’. Then Nilsen had tried to strangle him and then to drown him in the bath. The next thing Stottor knew he was sitting in a chair, and Bleep was licking him. Nilsen had spared him.

In the morning, he walked Stottor to the Tube station, wrote down his telephone number and told Stottor to call him. He never did. He sought hospital treatment for the bruises on his neck, the water in his lungs; a doctor told him he thought somebody had tried to drown him. ‘I thought if somebody is trying to kill you, they’re not going to let you walk out of their house.’ He did not go to the police. Instead for six months he just ‘blotted it out as a form of self-protection’, until Nilsen was arrested and the police came to interview him.

Stottor was a key witness at Nilsen’s trial. After that, he returned to Blackpool, where he became a female impersonator – ‘I got a bit of a name for myself.’ But panic attacks eventually prevented him from performing, and he drifted, as he put it, ‘into obscurity’.

Periodically he would emerge to talk about Nilsen. When I met him, he was being paid to take part in an Australian TV programme. He was filmed running down a hotel corridor, glancing nervously over his shoulder, in a clumsy caricature of fear. He was obliging in this, as one imagined he was in most matters. ‘A lot of people,’ he said, ‘might think I am jumping on the Nilsen bandwagon, but I’ve every right to. He has taken a lot from me.’

For a year following Nilsen’s conviction, Stottor wrote to him in prison ‘to try to confirm some things in my own mind about what had happened. But he just went on about how awful prison was, the food…’ Though Nilsen did give his reason for sparing him. ‘He said that what passed between us was a thin strand of love and humanity. The police, though, said he had no more room to house another body.’

I tried to find Stottor to talk to him for this article. There were some pictures of him on the internet – he didn’t look good – but no indication of where he might be found. Then I learnt that he had died. He was not even 60.

‘Oh, dear Carl!’ Masters says when I mention him. ‘He was such a sad man. At the trial he was the most pathetic witness – terrified! What was most interesting was what he said to me. He described what had happened – how the dog licked his leg and he revived. Nilsen snapped out of the demonic mood and spent the rest of the night putting extra blankets on him, rubbing his legs to revive him. And Carl, in his frightened little voice, said, “That man completely destroyed my life, because he’s turned my moral sense upside down. I don’t know whether he was my murderer or my saviour, because he was both, and I can’t cope with that.” He was haunted by what had happened to him. Haunted. So Nilsen did kill him in the end.’

Masters pauses. ‘For a long time,’ he says, ‘I thought to myself, “Brian – you are going to be his last victim.” Because everything that I know about him is in here,’ he taps his head, ‘and I can’t chuck it away. And when I get dementia in old age, it will still be there. But, thank God, I never did get dementia; and the way things are going I probably won’t.’ The smile is one of relief. ‘I’ll go from old age, but with a clear mind.

Des airs on ITV; a new edition of Brian Masters’ book, Killing for Company, is published on Thursday