The days of the hipster builder seemed to be numbered, after a construction firm has banned workers from wearing beards.

Gloucester-based business Mears has made facial hair taboo in order that dust masks can be fitted correctly, conforming with health and safety rules. The firm employs 15,000 workers nationwide.

In a letter to staff the company said: "Operatives who work in a potentially dusty environment - all of ours - must come to work clean shaven to be able to wear appropriate dust masks effectively."

It added the only exceptions are if a beard cannot be shaved for medical reasons, then a doctor's note must be provided.

If a beard is "worn for religious purposes" then a letter from a "church /mosque/synagogue /temple etc" must be handed to management.

In a concessionary move the letter said a goatee "may be acceptable as long as it does not impact the fitting of dust masks."

However, the measure was condemned by the Unite union as "penny pinching" and insensitive.

The union said: "While facial hair can affect tight fitting face masks - the cheapest option - other forms of masks which have their own airflow such as helmets, hoods and visors can be safely used with a beard."

Unite regional official for London Mark Soave added: "The arrogance of Mears is hair-raising. This is a highly delicate issue, which has huge cultural, religious and personal issues and where sensitivity should be the watchword. Instead members have been handed a decree from on high."

But Mears group health and safety director Mark Elkington told the Guardian: "We are pretty surprised that Unite, who claim to have the safety of workers at heart have taken this disappointing stance."

"The simple fact is that no dust mask can work effectively unless it forms a seal against the skin.

"That is not possible with a beard or even heavy stubble."