May's move came in a hectic week at construction boardrooms – Ken Chambers, Laing Construction's finance director, left his post, and Miles Roberts, Costain's finance director, announced his resignation.
May, who was previously Mowlem's construction managing director, will take up his new post on 24 September. Adrian Franklin, HBG's current boss, is moving to the HBG group board.
Franklin said he was delighted to have snapped up May, who left Laing in July. He said: "The thing that really attracts me is that he comes from a background of quality companies such as Mowlem and Laing, which we now count ourselves as being among."
Franklin will oversee HBG's civil engineering interests, which include operations in the UK, the USA, Ireland and the Netherlands.
May's move stunned the sector. One former colleague said: "I am surprised he landed a new role so quickly, but I suppose opportunities like that don't come every day."
Opportunities like that don’t come every day
Former colleague of Brian May
The announcement led to market speculation that May would attract former Laing colleagues, disgruntled at the sale of Laing Construction to O'Rourke, to HBG.
Laing confirmed this week that construction finance director Chambers had resigned from his post. He is understood to have left at the end of last month.
A Laing source hinted that Chambers' departure was the direct result of Ray O'Rourke taking over as Laing Construction's chief executive. The source said: "Acquisitions usually lead to two roles being redundant at the firm being bought – chief executive and finance director."
Costain finance director Roberts, who joined in May 2000, will leave the firm at the end of the year. He is moving to the same role at manufacturing group McBride.
Roberts' departure continues an unsettling period for Costain. The firm's chief executive Stuart Doughty and chairman David Jeffries have only been in their roles for a few months.