As is the way with the best cosmetic work, Maria Matthews’s friends couldn’t quite put their finger on what she’d had done.

The 51-year-old’s wrinkles appeared to have been gently smoothed away, her cheekbones were more pronounced and her face looked slimmer. Her jawline seemed firmer, her skin plumper and creamier and her eyes were now sparkling.

But Maria hadn’t been under the surgeon’s knife, or succumbed to Botox injections, fillers or an extreme skin treatment.

Instead, the secret behind her stunning transformation was something altogether more prosaic — a visit to a hair salon.