Ashley Stobart was 18 when she first booked in for lip fillers. For more than a decade she regularly had the injections in just about every part of her face. The jabs – medical-grade gels that are injected and sit beneath skin – add volume, creating a plump, pillowy pout and defined cheekbones.

Once the preserve of middle-aged women looking for an anti-ageing fix, the number of teens and twentysomethings opting for them has soared. A survey of 18-to-24-year-olds revealed seven per cent had a cosmetic lip enhancement, while 68 per cent knew someone who had.

Why? Many speculate the trend is driven by reality TV stars and celebrities who increasingly admit to, or appear to have had, cosmetic procedures.

Ashley has a simpler explanation for her decision: ‘Vanity,’ she says, bluntly.

When her family questioned her choice, she shrugged it off. ‘They’d say, ‘Why have you got these big lips and big cheeks?’ I’d think they were trying to tear me down – now I realise they were right. I didn’t look like me any more.

‘But fillers are addictive. You don’t realise you’ve started to look a bit weird.’

Eventually, she admits, she didn’t recognise the person she saw in the mirror. So in March, now aged 34 and a mother-of-three, Ashley, who is married to Edd Stobart of the haulage family, took drastic action – she had her fillers removed. But then, left with loose, uneven skin, she had a surgical face and neck lift, and a lips lift – procedures that are more common for women in their 50s and 60s.

Ashley, who presents the podcast Nip, Tuck, Not Giving A…’ says: ‘Years of filling… f*****g with my face, I didn’t look like me any more. The surgeon was squeezing filler out of my face.’

The operation ended up lasting nine hours – and Ashley believes that her story could serve as a warning to others.

‘These lunchtime treatments can have a profound effect on your face, years and years on,’ she says.

‘We were told that filler disappears after a few months, and then you have it done again – but that isn’t the case.

‘We are going to see many more women needing surgery at a younger age.’

Dr Julian De Silva, a specialist in facial plastic surgery, agrees, saying: ‘Increasingly women are coming to me about facial ageing in their 30s. Often it’s because they’ve had fillers.

‘Filler can accumulate, it doesn’t always completely dissolve naturally or with hyaluronidase [an enzyme that surgeons can inject to break down the gels] and it can be really difficult to remove.

‘One patient I hadn’t seen for five years came back for facelift surgery and I almost didn’t recognise her because she had so much volume added to her cheeks, lips, chin, jawline.

‘She was having it added every six months and it just accumulated. We dissolved as much as we could. But patients often require surgery as their skin ends up stretched.’

Dr Sophie Shotter, trustee of the British College of Aesthetic Medicine, says: ‘The face essentially disintegrates – the volume melts and leaves saggy skin. The two main risk factors are how much filler the patient has had and the period of time over which they’ve had it.

‘Even though you’re not supposed to have fillers before you’re 18, we know less reputable clinics do it, so I’m not surprised they hit their 30s and end up with skin laxity and needing surgery.’

Actress Lindsay Lohan, 38, recently debuted a dramatically sculpted face which UK-based aesthetics doctor Johnny Betteridge claimed was a combination of ‘good surgical and non-surgical work’ to get rid of fillers.

He said she previously had ‘signs of over-filling’.

Singer Christina Aguilera, 43, has also appeared to have dissolved her fillers and had a facelift and eyelift, he claimed, after ending up with ‘too much dermal filler’ leaving her with a ‘pillow face’.

Dermal fillers are among the most commonly requested procedures in Britain, alongside laser hair removal and Botox injections. Botox works differently to fillers, using a toxin to temporarily paralyse muscles to smooth out wrinkles, and is only available on prescription. An estimated 900,000 injections are given every year.

But it’s impossible to know how popular cosmetic fillers are as sales aren’t regulated and anyone can legally perform them.

They are most commonly made from a lubricant called hyaluronic acid, which is naturally found in the fluid of the eyes, joints and skin. An essential part of anti-ageing treatments, it is added to many skin and haircare products.

When injected in small amounts as a gel, it adds volume which plumps and smooths wrinkles and restores lost structure. The effects were said to last for up to two years, as it degrades over time, which is why clinics tend to recommend repeat appointments after several months.

But MRI scans suggest this might not always be the case – one study found evidence it could remain for up to 15 years.

Journalist Alice Hart-Davis, who used fillers for years and runs online advice site The Tweakments Guide, wrote in the Daily Mail last year that an MRI scan of her face revealed 35ml of fillers – roughly equal to the total amount she’d injected in her lifetime – under her skin, four years after her last treatment. Dr De Silva says: ‘Some of these hyaluronic acid fillers don’t disappear – they can stick, particularly under the eye, and can persist for years.’

This doesn’t have to be a bad thing, says Dr Shotter, who carried out Alice’s MRI scan.

‘We know it hasn’t caused problems or slid around her face, and she looks great,’ Dr Shotter said. ‘But if she wanted it dissolved would it cause a problem? Yes.’

And Alice, 61, has been restrained in the amount of filler she has used.

Problems come when women want a look popularised by reality TV stars – big lips, enhanced cheekbones and jawlines – and use a lot of filler to do so.

‘For someone emulating them who has a slightly weaker receding jawline, or not much mid-face structure, that can take a surprisingly large amount of product to replicate,’ Dr Shotter says. ‘Doing that leads to a lot of distortion and stretching very quickly.’

Cheap bundles – often called ‘Kim K’ or ‘Kylie J’ packages, after Kim Kardashian and Kylie Jenner – encourage women to return for more, she adds.

Aenone Harper-Machin, of the British Association of Plastic, Reconstructive and Aesthetic Surgeons, has treated increasing numbers of young women in her Chester clinic who used fillers to correct creases under the eye.

‘They keep layering it on,’ she says. ‘Eventually they come to us wanting surgery as they can’t correct it any more with filler and it gets heavier and heavier – the weight of filler in the face starts to have an impact.’

Genetics also play a role in how well fillers work, Dr De Silva says. ‘Some people age faster and have hypermobility in the skin – it gets looser quicker.’

A study has found that 68 per cent of those injecting filler had no medical training.

Yet there are delicate blood vessels in the face which, if injected with filler, can cause tissue to die and lead to blindness. A proposed Government licensing scheme – which would make those doing fillings meet standards of training and competence – was stalled by the election. There are also dozens of different types of filler used in the UK.

Ashley says women end up with ‘all these different brands of filler…and different injectors who all inject differently’.

Dr Shotter also warns that some cheap filler products may not have a good safety profile.

‘A lot of them, I wouldn’t touch with a bargepole,’ she says.

Dr Harper-Machin recommends searching for a registered practitioner on the Bapras website and to ask for the packaging of any filler so you know what you’re being injected with.

Ashley insists her filler days are over. She has launched a skincare venture, Cosmetic Consult, which offers at-home overnight exfoliating treatments to perfect skin and get rid of fine lines.

‘I think we’re coming to the end of this trend,’ she says. ‘Ladies who’ve been there and done that don’t want their daughters to do the same.

‘It has to be about being educated on doing the right thing, which, in years to come, is still going to look good. And the filler route isn’t that.’