May, 65, will step down in September after more than 10 years with Renew, handing over to Paul Scott who joined the board two years ago as director of engineering services.

During his long career May worked for Mowlem for many years before becoming chief executive of Laing Construction before it was sold to Ray O’Rourke and then chief executive of HBG Construction, which was later sold to BAM.

Scott, who has been with the Renew group for over 15 years, was managing director of Shepley Engineers, the group’s principal nuclear business, which has shown substantial growth.

To strengthen the £500m turnover firm’s senior management team Andries Liebenberg, managing director of Renew’s largest business, Amco Rail, has been appointed to the board with immediate effect.

In a trading update this morning the firm said it had operated above expectations in the first six months of the year, with an increased order book and reduced net debt.