But the signs aren’t as easy to spot as they used to be. Gone are the days of “cat on a wet bike” face-lifts and Mr Spock eyes. Even boob jobs are getting so good that it can be difficult to tell the fakes from those that are just, well, a bit perky. “A good job is one that looks natural,” says the leading plastic surgeon Kevin Hancock, of the British Association of Aesthetic Plastic Surgeons (BAAPS — yes, really). “It can be extremely hard to tell unless you’re a plastic surgeon.”

Until now, that is. In the interests of anthropology, Style has assembled a fail-safe guide to decoding the body’s hidden secrets. There is no escape.

GIVEAWAY 1: SCARS

Most surgery leaves its mark: you just need to know where to look. With a face-lift, there may be scars tucked behind the ears or, depending on the skin’s elasticity, more obvious ones around the front of the ears, edging onto the cheek. Facial liposuction, meanwhile, leaves tiny scars on the chin.

Scars on the body are trickier to assess. For boob jobs, look underneath the breasts themselves, or by the armpits, where implants are most commonly inserted. They can also be inserted at the bellybutton — but don’t confuse these scars with liposuction scars, which normally appear on the hips or next to the bellybutton.

Most difficult of all are nose-job scars. These are usually inside the nose, so unless you’re on really familiar terms with someone, scar-spotting is probably not the easiest way to find out.

GIVEAWAY 2: BIG BOOBS, SKINNY BIRD

Look for features that don’t quite fit, such as large breasts on a lollipop body. “It’s difficult to make a girl who is thin and flat look natural with a set of large implants,” says Hancock. Similar giveaways are women with line-free visages, but gnarled hands and sagging necks, or thin older women with unnaturally plump lips. “Even if it’s good work, you can always tell when something doesn’t quite fit,” says the make-up artist Ruby Hammer. “Go with your instinct and you’re usually right.”

GIVEAWAY 3: SKI-JUMP NOSE

This turned-up number is the standard-issue nose among plastic surgeons. It pops up everywhere — standardised operations are one of the main reasons everyone in LA looks the same — so, if you see one, you can be fairly sure it’s fake, especially if the nose looks too small for the rest of the face, like a pebble on a prairie.

GIVEAWAY 4: BOTOX EYEBROW

Botox is the UK’s number-one procedure and, in most cases, it’s impossible to tell who has had it. With long-term use, however, the signs become more obvious. Worst of these is Botox eyebrow, where the tips of the brows jut menacingly upwards. Around the mouth, the upper lip becomes flat and rubbery, like a rhino’s, and doesn’t crease, even to slurp from a straw. And because Botox is used to treat sweating, people eventually stop perspiring, making them look like waxworks.

GIVEAWAY 5: THAT UNNATURAL FEELING

“You can definitely feel stuff that’s been injected into the face,” says Hammer, who has felt more faces in her time than you would care to think about. “Even cheek implants feel hard and unnatural.” The same goes for breast implants — unlike real breasts, you can squeeze them fully, like balloons, which is essentially what they are. (Mind you, if you’re getting that close, you’ve probably worked out they’re fake anyway, or are past caring.)

GIVEAWAY 6: BUBBLY LIPS

As people get older, their lips disappear into their mouths, so older women have thinner lips. But lip jobs can be subtle, and just because she hasn’t got a pair of air bags on her mouth, it doesn’t mean she hasn’t had work done. Look for a thin line of filler along the ridge of the lip — if it’s been done unevenly, so much the easier. The lip may be puffier on one part than another, often at the top.

GIVEAWAY 7: MOVING HAIRLINE

Face- and brow-lifts necessarily yank up extra skin, resulting in a moving hairline — at the top for brow-lifts, at the side for face-lifts. This can be difficult to spot, but if you know your target well, and she has suddenly got an extra 2in of forehead, it’s safe to assume that she has gone under the knife.

GIVEAWAY 8: BREAST RIDGES

You don’t always get full-frontal nudity in order to assess the fakeness or otherwise of breasts. Presented with a pair in a bra, though, there is one way to tell if they’re not real — ridges on the breast line. Look at the upper part of the chest: if it’s fake, it will protrude too much and give the overall impression of being too high.

If you’re still none the wiser, the best way to work out whether she has had anything done is to think about whether she’s likely to have had anything done. After all, who do you think is going to fall for the charms of the knife: an affluent thirtysomething fashionista from Chelsea, or a female truck-driver from Devon? Failing that, of course, you could always just ask.

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