It has been more than a year since the operation, but Alistair is still furious about the results. “I paid £8,000 and they mutilated me,” he says. “It was butchery. My partner said it looked like a war wound. My erection is basically ruined.”

In July 2017, the 55-year-old decorator, from London, became one of a growing number of British men to have a surgical penis enlargement. Talk of enhancement was once the preserve of promotional spam mail for bizarre-looking pills and pumps; now, it is serious clinical business. British clinics, which have taken consultancy rooms in Harley Street and in UK cities including Manchester, Sheffield, Birmingham and Leeds, report record numbers of patients calling on their services. One practice, the London Centre for Aesthetic Surgery, has gone from performing a handful of penis procedures annually when it opened in 1990 to more than 250 in 2017. Between 2013 and 2017, members of the International Society of Aesthetic Plastic Surgery carried out 45,604 penis enhancements worldwide. Previous numbers are unknown; the procedure was considered such a minority concern that it wasn’t included in surveys. This increase in demand seemingly caters to a growing anxiety about penis size, but it is by no means a risk-free procedure. For Alistair, dreams of a larger penis were overtaken by infections, lumps and an erection that no longer rises above a 45-degree angle. And he is not alone. In recent years, the General Medical Council has recorded stories of “wonky penises” and erectile dysfunction following surgery. In Stockholm, last summer, a 30-year-old man died after suffering a cardiac arrest following an operation to enlarge his penis.

***

At his Harley Street clinic, Dr Roberto Viel is explaining how a typical enlargement works. First, surgeons sever the organ’s suspensory ligament, causing it to hang an inch or two lower, giving the impression of extra length. They then extract fat from the patient’s stomach and inject it into the penis shaft, increasing girth by around two inches. Erect, it’s worth noting, it remains roughly the same size, suggesting the motives for many men are not necessarily to enhance either their – or a partner’s – sexual experience.

The procedure, which can cost more than £5,000, lasts a little over an hour, but causes enough residual discomfort that doctors recommend patients take a week off work. The penis remains bandaged for 10 days. Sex is off the cards for a month. Erection suppressants are prescribed to avoid stitches being ripped open.

“Operations are very safe,” says Viel, who founded the London Centre for Aesthetic Surgery with his twin brother Maurizio. “Perhaps 95% of our patients are very happy. Where they are not, it is often to do with expectations. Some men want 10 inches when nature gave them four or five. I have to say, gently, ‘This is not possible. I am not a miracle worker.’”

William O’Connor, a 38-year-old mechanic from Northampton, is one of his satisfied customers – and it’s easy to understand why. Think of a large can of aerosol deodorant and you have, roughly enough, his new dimensions. “There was one woman who took one look at it and just went, ‘That thing is coming nowhere near me,’” he says. “But mostly it goes down very well. I’ve seen a lot of eyes light up.”

Though generously endowed by nature and confident enough in his body to have appeared in some adult films in his 20s, O’Connor decided to enhance his girth in 2013. “It was just something I fancied,” he says with a shrug. “Some men have hair transplants or belly tucks. I wanted a truncheon in my pants. My whole life I’ve enjoyed impressing women; this was just an extension of that. You could call it a gentlemanly thing to do.”

O’Connor says he had no concerns beforehand (“My main worry was having the anaesthetic – I’m scared of needles”) and no regrets afterwards. The pain was manageable and there were no complications. He views the procedure as akin to working out. “I’m not obsessed by my body – I have too many other things going on in my life,” O’Connor says. “But I’m proud of it and I like that it’s in good shape – every part of it.”

The surgery should have no impact on fertility; O’Connor has since married and fathered two children (he also has four from a previous relationship). “I met her after the op, but she was a family friend and knew I’d had it done. I’ve never asked if it was a plus point.”

***

Amr Raheem is an andrology specialist (meaning his focus is on medicine relating to men) at University College London Hospitals, as well as a surgeon at International Andrology, a private clinic in the capital. Over the past 15 years, he has carried out more than 250 enlargements. “There is no typical patient,” Raheem says. “All professions, all ethnicities, married, single, gay, straight, rich, poor. It’s across the board. And all ages. I’ve worked on men in their 60s – I don’t know if they go out and use it afterwards. Early 20s, I won’t do. These are still boys. They must get to know it before they change it.”

Patients come in all shapes and sizes: “I’ve had men who are already large enough. I had one say he wanted to be like a milk bottle. Impossible.”

If there is one unifying factor, it is a lack of confidence about what nature has provided. The average length of a British penis is, according to a 2016 King’s College London study, 5.16in erect and 3.67in flaccid. Only 0.14% of men have what one University of California study defined as a “micropenis” – that is, less than 2.5 inches when erect. Nonetheless, study after study shows dissatisfaction remains widespread among men.

“These are the men who come to us,” Raheem says. “They are not necessarily small, but they want to feel more confident. In front of women, yes, but in front of other men, too, down the gym, that sort of thing.”

Many of his patients, he adds, have previously “avoided sex or situations where they would be exposed, out of embarrassment. So this makes them happier.”

Not all operations leave happy customers – infections and scarring are both potential side-effects (“This is the same as an operation of any kind,” Viel says). Some men report a decline in angle after the suspensory ligament is cut, but according to David Ralph, a professor of urology at UCL, “By and large, patients don’t complain about that. The operation doesn’t change the erect length at all – this is only for men who have anxiety about how they look in the changing rooms. The average increase in size is 1.3cm, less than the diameter of a 1p coin. In my clinics, I show patients one of these and ask if they still think it is worth it. Less than 5% decide to, and of those who do, the satisfaction rate is just 20%.”

Occasionally, the cut ligament leaves genitals lopsided when flaccid, and pointing off to the left or right when erect, as Francis Tilley, director of London clinic Androfill, explains. “Ligaments are there for a reason,” he says. “If you start cutting at them, the stability of the penis will be reduced: the erection will be lower and less straight.” Tilley’s practice offers the operation, but its website clearly identifies it as high risk.

One Stockport-based surgeon, Ravi Kant Agarwal, was struck off (though later allowed to practise again) after botching two procedures. One of his patients, the General Medical Council heard, was left with a penis “bent like a boomerang”. Agarwal was criticised for failing to explain potential complications and misleading patients about the possible outcome, as well as for not having anaesthetic backup during the operations.

Alistair decided to have the operation after 40 years of anxiety. “I played Sunday football and dreaded the changing rooms,” he says. “It’s not so much the length as how thin and scrawny it was.”

He married, had children and learned to live with his unease. Then, four years ago, after separating from his wife, he asked a new partner how he measured up to her ex-husband. “It was a stupid question,” Alistair admits. “It’s pathetic that I cared at my age – but I did. To start with she told me it was fine, but I kept pushing and, eventually, she just told me: his was bigger.”

Alistair took out a £5,000 loan to add to £3,000 of savings, and paid to go under the knife. (Surgery is difficult to obtain on the NHS, though it can be offered for psychological reasons, or to correct a true micropenis.) “It was the worst thing I’ve ever done,” he says. “The pain afterwards… I couldn’t sit, I couldn’t stand. It was beyond anything they told me to expect. The wound got infected, and when they gave me antibiotics, it kept seeping pus. The scarring has barely faded even now.” He says the fat injection became lumpy, while his erection no longer stands straight. “It just doesn’t look right. It’s deformed.”

Not long after the operation, he and his partner – who had repeatedly insisted he should not have it done – split up. As we speak, he is preparing for one of his first dates since their separation. “I’m already worried about what she might think if we get intimate,” he admits.

***

Thomas Modecai, 37, a teacher from Crewe, has struggled with the size of his penis for most of his life. “When I was 14, I shot up to 6ft but my penis stayed the same,” he says. “I felt like a man with a child’s penis. And it’s affected everything: my relationships, my confidence, even my desire to have children. I worried they might have the same issue.”

The only person who has ever seen him without clothes is his wife. “But even with her – we’ve been married 14 years – I was still anxious.”

After being dismissed twice by doctors (“One said, ‘Don’t worry about your penis, but you’re overweight’”), Modecai contacted Andrology International and, in August last year, paid £6,800 for a length and girth boost.

“My wife didn’t like the idea,” he says. “But this had been bothering me for 20 years. I’d already tried pills and potions – useless stuff you see advertised in spam – and I was exhausted. I needed it fixing.”

Since the surgery, he has felt happier and more confident. “I’m not exactly skipping round the house naked but, you know, maybe once I lose that weight,” he says. “And we’re now thinking about children.”

I ask for his pre-op dimensions. He doesn’t want his exact measurements reported, but they are surprising: while flaccid, he was smaller than most men; erect, his penis grew significantly. Modecai, it seems, experienced two decades of stress despite the fact that, fully extended, he was bigger than the UK average. This apparent contradiction does not surprise Angela Gregory, a psychosexual therapist based at Nottingham University Hospitals NHS Trust. “Penis enlargements can be about a lot of things,” she says. “But the amount of anxiety a man experiences rarely, in my experience, correlates with his actual size.”

The sheer symbolism of what’s in a man’s pants may be a factor. As Harrison Pope and Katharine Phillips write in their book on male body obsessions, The Adonis Complex, genitals have been equated with “virility, procreative potency, and power” throughout history. This has been compounded by an apparent rise in general masculine vanity. Figures from the British Association of Aesthetic Plastic Surgeons show the total number of male procedures doubled between 2005 and 2015, with breast reduction, rhinoplasty and neck lifts especially popular. For those in need of rejuvenation, surgery is cheaper and more easily available than ever.

Furthermore, Gregory highlights two other recent developments: the proliferation of pornography and the rise of TV shows where brutal physical objectification has become, for the first time, an equal-opportunities phenomenon.

“Young men generally become preoccupied with the size of their genitals when they compare with others,” she says. “Historically, this was limited to changing rooms or the odd top-shelf magazine. But now there is this almost routine exposure to porn via smartphones. And that is creating a generation of men whose expectations of what they should look like are entirely unattainable.”

Added to that, she says, is the popularity of shows such as Love Island where objectification comes as standard. In the summer of 2017, one male contestant was described as having “a penis like a baseball bat”; it was, unequivocally, a compliment. None of this objectification is new, of course: it’s just new for men. “But that doesn’t lessen the impact,” Gregory says. “For the individual who is going through the trauma of fearing his penis is too small, this is still devastating.”

All this might be leading to more than simple image anxiety; some have pointed to a new mental-health issue they term penile dysmorphic disorder. “It is a minority of men – and we don’t know how many – but it certainly exists and it’s as damaging as any other body dysmorphia,” says Professor David Veale, of King’s College London, an authority on health anxieties. “These men might seek out surgery, and for a few months they will be happy with the results. But then the same anxieties reappear. So, they seek out further surgery. It becomes a circle. But you cannot keep making your penis bigger. This requires therapy.”

Largely, he says, these cases remain undisclosed. “Those who suffer don’t necessarily realise themselves, and rarely admit it. It is an invisible illness.”

So how can we be sure it really exists? “Because the number of men seeking surgery, or the growth of this strange industry selling pills and other so-called enlargement remedies, these numbers do not map up with the numbers of men who actually have a significantly smaller penis than average,” Veale says. “So, these men are worrying about – and seeking solutions for – a problem they do not have.”

Veale’s theory chimes with the experience of a retired sales manager I meet in a drab Sheffield consultancy room. A lifelong bachelor, Eric Bell, 68, is charming and well-dressed, if, with a beard tinted blue, a touch eccentric. He is also preparing for his third penis enlargement – an operation that, judging from the sizeable member already between his legs, is unnecessary. “I’d just like it a bit fatter here,” he explains, circling thumb and middle finger around the top of his shaft. “I’m single, but it makes me happy knowing I have something eye-opening down there.” We spend five minutes discussing the merits of this before he asks his own question: “Can I put it away now?”

Bell says he had his first enlargement in 2015, a year after suffering the trauma of his brother drowning in York’s River Foss. “I suffered severe depression,” he says.

Are the two things linked? “Possibly,” he says. “I don’t know. I don’t think about it.”

Bell is a patient at Moorgate Aesthetics, which has head offices in Doncaster. When I ask managing director David Mills if this may be one client who doesn’t need any more girth, he waves away the concern. Bell, he says, knows his own mind, and has passed a psychological evaluation. The operation goes ahead.

This evaluation is something all clinics I speak to insist on. It involves a patient meeting with a surgeon or psychologist to have their general mental wellbeing assessed. If there is any hint of underlying concerns, problems or mental health issues, the operation does not go ahead. But, given that such a refusal would mean clinics losing £5,000 a pop, one does wonder how rigorous these assessments are. Is the entire industry just profiting off insecurity bordering on dysmorphia?

Dr Roberto Viel thinks not. “I tell my patients we can give you a bigger penis, but we cannot make you happy,” he says. “You must be happy first, in your heart and head. If not, this operation is not for you. All it would mean is you are still unhappy – you just have a slightly bigger penis.”

Professor Ralph at UCL believes that some clinics are feeding patients’ unrealistic expectations. “Initially, they don’t see doctors, they see sales people. It’s a hard sell: ‘We can get you an extra inch or two.’ I’ve been practising in the NHS for 30 years: if it was that easy to increase the length of a normal penis, I’d be in the Mediterranean on my cruise liner now.”

Ralph thinks that “penile stretchers”, marketed under the name Andropenis, can be just as effective; but few men are prepared to make the commitment of wearing a traction device for six hours a day for six months. He also points out that, for men with an unhealthy BMI, weight loss can be enough to make the penis appear bigger.

In a last brief conversation with Alistair, he asks if I would ever consider going under the knife. I tell him I’ve seen such a bewildering array of shapes and sizes over the past few weeks, I don’t even know what normal is any more. If it does the job nature intended, I say, that should be enough. For many men wanting an enlargement, it’s probably not so much about what’s in their pants as what, somewhere along the way, has got into their minds – and that can’t be fixed by a fat injection and a severed ligament.

Alistair thinks about this and appears to agree: “Once it’s in your head, it’s difficult to let it go – even after you’ve had surgery.”

• Alistair’s name has been changed.