The pay cuts apply to 500 staff on furlough leave as well as those working from home and on projects like the Nightingale hospital in Exeter BAM is in line to deliver.

Chief executive James Wimpenny said: “Like many other businesses, BAM is facing unprecedented challenges during this period as we balance our desire to support all our employees through these times, with the need to protect the future sustainability of the business.”

He added: “The new ways of working mean we are only operating at around 55% productivity across the business which has an impact on the income we will receive from our clients.”

Senior management took a 20% pay cut a month ago, bonuses were deferred and board pay rises forfeited.

Now BAM has stopped all non-business critical spending and is implementing all other cost-saving measures it can take to reduce cash going out of the business in the next few months.

A spokesman for the firm said: “Obviously these are unprecedented times for all businesses, not just ours. Almost 500 colleagues are furloughed, and site and office working practices have changed out of all recognition.

“Our employees have been amazing, keeping the business going and staying safe.

“We have built a Nightingales facility and adapted many other NHS facilities to help in the effort to treat and cope with covid-19.

“We are extremely proud of them because they remain highly-motivated, highly effective and highly regarded.

“We are not announcing redundancies and will do whatever we can to continue being a resilient employer in the months and years ahead.”