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Debenhams said that while teenagers wear their trousers below their hips, in later life the only way is up.

This reaches a peak at the age of 57 when a man’s trousers are as as high as seven inches from his armpits.

The high street chain said the change is due to a shift in body shape.

Paul Baldwin from Debenhams said: “Our findings are very important because the position of the waistband determines how men’s trousers are tailored. These results will help our designers produce trousers which take body shape into account.

“However, our hardest task continues to be persuading men to confront the fact that their trouser waistbands have risen. From our experience, men still prefer to assume that their trousers no longer fit because their legs have suddenly grown.”

The store also found that when men got older their waistband lowered again. By 65 it was three inches above the natural waist, and one by the age of 75.