The deal lifts Kier into fourth place in the ranking of UK construction contractors, above Morgan Sindall and Interserve, behind Balfour Beatty, Carillion and Laing O’Rourke.
Kier and May Gurney have spent the past few weeks working to make the merger as smooth as possible so as not to cause any disruption for clients.
Kier Group chief executive Paul Sheffield said: “We are delighted that our bid for May Gurney has finally reached fruition. This gives us a services division that is not only bigger and stronger, but which has significant highways maintenance experience. We believe that our offering is now as comprehensive as it can be.
"Importantly, May Gurney and Kier share similar values which will go a long way towards the successful integration of both businesses. I would like to take this opportunity to welcome our new employees and trust they will enjoy playing a part in the future success of Kier Group.”
May Gurney business development director Greg Michael added: “We are excited about joining forces with Kier. May Gurney’s range of services complement Kier’s existing offering and a combination of the two creates a market‐leading and well‐balanced business and enhances our joint prospects.
“Both companies have a clear and genuine commitment to customer service and quality and we remain focused on delivering an excellent service to our long-term clients and their customers.”
Rebranding will take place over the coming weeks and May Gurney’s office in Trowse, Norfolk, will remain as a shared services centre for the enlarged group.