Martindales, whose business includes the repair, manufacture and supply of timber windows, wants to see a licensing system similar to the gas installation industry’s CORGI scheme where installers have to complete a recognised training course.

Phil Martindale, the company’s managing director, described two-thirds of replacement window and door fitters as “cowboys”. He also said some new businesses setting up in the sector did not know about the important Part L (energy efficiency) of the Building Regulations.

“The best they can provide is a window or door that might do the insulation job it was supposed to – but the worst could be anything from a huge devaluation of the house because more and more house sales are dependent upon the right documentation, through to the installation of an incorrectly specified piece of glass that somebody could too easily break or even fall through.”

Mr Martindale said the industry also urgently needed to educate consumers and householders about installation standards demanded by FENSA (Fenestration Self-Assessment Scheme).