Barratt is rolling out the random testing regime amid fears of substance abuse and a 20% rise in injury rates.

During the year, the house builder’s injury incidence rate increased to 462 (2017: 379) per 100,000 persons employed, including trade contractors.

The firm said: “We have already undertaken a review into factors that have contributed to this increase and will be working with our management teams to drive improvements in the prevention of injuries.”

Barratt said it was also meeting the challenge of increased activity levels across the industry in terms of site openings and production volumes combined with shortages of skilled workers which has contributed to an increased risk on sites.

The firm said that as part of a move to ramp up its focus on health and safety it had also decided to enhance its drugs and alcohol policy and commenced a programme of random sampling across the business.

Barratt said: “Our aim is to achieve a reduction to a rate which is more reflective of our business commitment to health and safety.”