Plastic surgery is becoming a billion-pound industry in the UK. More of us than ever are ready to pay, and suffer, for a more perfect body or less lined face. Susie Mesure watched a practitioner at work

A pert pair of buttocks faces upward; the woman's body prone like a sunbather, a paper G-string preserving her modesty. But for the butcher's black markings on her tanned skin and the surgeon hovering above, she could be lying on a Riviera beach, the envy of her fellow holidaymakers. It seems inconceivable that this perfect body is the target of the liposuction procedure that Roberto Viel, giant syringe in hand, is poised to perform – and yet it's true.

In goes the needle and out comes the fat – or the little of it that exists on her size-10 frame – sucked into the cosmetic surgeon's equivalent of a turkey baster. And again, and again, until nearly a pint of the stuff has been dispersed into several large test tubes ready for the morning's main procedure: a fat transfer to the breasts, otherwise known as an upmarket boob job.

"It's a two-in-one operation, but she only pays for one," says Dr Viel, standing in his Harley Street operating theatre. "Afterwards, she will have a smaller waist, smaller thighs, bigger breasts. Perfect. That's what every woman wants."

I find it hard to argue, mainly because I'm concentrating very hard on not throwing up. Or fainting. I am nauseous and my legs are wobbling, but that's nothing compared with how Marta, the 45-year-old under the knife, is going to feel once her local anaesthetic wears off and she begins the three-week task of recuperating from what strikes me as an act of pure misogyny. Or it would if it hadn't been Marta's idea. "It was for me. I want to feel good in a bikini. I like men looking at me," she tells me later. (Her husband included, apparently. He's just "happy because I'm happy", she says.)

Grim as it was seeing the fat come out, it is worse still when Dr Viel, 50, who runs the London Center for Aesthetic Surgery, starts re-injecting it. I wince each time the syringe pierces Marta's flesh, but manage to keep looking, albeit only by peering through the holes of my spiral-bound notebook. There's a certain fascination about watching someone sculpt a living human form, his hands pummelling away at Marta's breasts to squeeze the fat into the right shape. Dr Viel, who admits breast augmentation is his favourite procedure, steps back to admire his work. "Now there's a nice projection. Before she was flat." Although her body will reabsorb some of the fat, he thinks the operation will leave her one cup size bigger, increasing her chest to a C cup from an A/B before, which incidentally isn't my definition of flat.

Minutes later, Dr Vial's needle is puncturing a fresh victim. A face this time. Over and over, each prick drawing fresh blood. Briefly, before gravity prevails and the viscous liquid drips down her cheeks, the dots resemble a Maori mask, but one painted in gruesome blood red, not white. This scene of torture is being carried out in the name of beauty, its target desperate to buy herself a few more years of youth. She is Christine, a 38-year-old mother of two, and she is here for an £800 procedure called platelet facial rejuvenation. But it looks more like a vampire facelift to me.

This time Dr Viel's syringe contains Christine's own blood platelets, which he is injecting back into her skin. The idea is they will stimulate her own skin cells to produce more collagen and elastin, tightening up her skin. She admits that "not many people will notice", but says she'll feel better about herself. "Sometimes it's nice to have a nice blank canvas when clothes and make-up aren't enough."

Christine has opted for one of the new so-called "non-invasive" cosmetic procedures that are taking the industry by storm. Fresh figures out this weekend show that people are increasingly shunning traditional cosmetic surgery like Joan Rivers-style facelifts, in favour of non-surgical procedures such as chemical peels, laser treatments, and the likes of that blood-red mask. A new report by the market research group Key Note found that in the UK the number of non-surgical procedures carried out between 2005 and 2009 soared by 219 per cent, outstripping growth of 175 per cent in the entire cosmetic surgery industry, which clocked up just over half a million procedures at the end of last year. Key Note, which surveyed 1,000 men and women, predicted that the value of the entire cosmetic surgery industry in the UK would hit £1.1bn by 2014, up from £536m at the end of 2008.

Certainly, demand for treatments such as Botox is keeping Dr Viel very busy. He has a packed day, squeezing in the women – and men – queuing up for a dose of the magic toxin in between his stints in surgery. Given its controversial reputation, Botox is amazingly popular. Francesca, 37, has been a fan for the past four years. "Why not? Life is so short. Whatever makes you happy, you should do it. Plus, I do really believe that more doors are open for you if you look good." Jenny, 45, a recent Botox convert, says of her new lineless look: "I've had lots of compliments. It's been extraordinary. People keep saying, 'You look so great. What have you had done?'" Martin, a 46-year-old hairdresser, adds: "It really freshens up your skin and makes you feel better."

Most of Dr Viel's patients start attacking their wrinkles as soon as they hit their early thirties, never mind that it costs upwards of £325 a pop. "It helps to slow down the ageing process. It's better to have it done young so the patient will reach their forties and fifties with not too many deep lines," he says, crossing his office to peer at my forehead. If he could frown, he would. "You need it," he tells me. I'd be offended, but it's probably true and for a minute I'm tempted. But then sense prevails and I remember that I find it hard enough making time for – and affording – a hair cut, let alone the biannual injections I'd end up craving from here on in.

I also know it's a slippery slope once you start. How else to explain the 46-year-old Californian mom anxious to remain nameless who has popped in to have her elbows done? Yes, her elbows. Not with Botox, this only works on lines not loose skin, but Restylane, the cosmetic equivalent of Polyfilla. "I'm really self-conscious about showing my arms. My elbows are like a 90-year-old's," she says. It's true that after the jabs they are a little less wrinkly, but, well, they're still elbows.

That said, who am I to judge what makes people feel better? I certainly can't comment on why one in three of Dr Vial's patients ring his Harley Street doorbell. It's because they are there for penoplasty, which is the technical term for enhancing someone's manhood – lengthways or widthways, although I'm told only the latter will withstand an erection. I should be disappointed that the one man lined up for the op today, a male version of Marta's fat transfer to her breasts, has chickened out of letting me watch – but I'm secretly delighted. It's been hard enough banishing the image of Marta's liquid fat, which incidentally looked just like Tropicana's bitty Sanguinello red orange juice, from my head, so it's safe to say that penoplasty would have scarred me, never mind its recipient, for life.

Some names have been changed