A hairdresser has revealed a hairstyle women should avoid if they are aged over 50. George Northwood said while an S-shaped bob is a “powerful” cut, for middle aged women it will look “dowdy”.

Mr Northwood, dubbed “King of the 21st Century bob”, told the Daily Mail that while a less-structured, S-shaped, blown up bob looks great on actor Zendaya, it is nevertheless “quite a middle-aged hairstyle.

He added: “On someone who is middle-aged it’s going to look dowdy. Granny chic looks different on a 50-year-old.”

The hairdresser defined his own take on the cut as being slightly undone, even if straight and smooth, with a natural feel.

His version is known as The Alexa and named after the model and TV presenter Alexa Chung, who is Mr Northwood’s muse.

He told the Mail he loves the “power of the bob”, describing it as a “kick-ass, powerful statement cut”.

Vidal Sassoon popularised the bob in the mid 1960s, with fashion designer Mary Quant among those to perfect the look.

Celebrities still sport the look, with Rihanna, Britney Spears, Keira Knightley and Jessica Alba all having had bob cuts.