Hamer has been on gardening leave for several weeks prompting rumours in the industry about his looming departure.
Sir Robert McAlpine announced changes at the top in an email to staff this morning.
It is understood to come as McAlpine struggles to bed down its new operating structure, which switched from a regional to a national sector-based operating model.
The statement to staff said: “Over the past seven years as chief executive Paul Hamer has led our business through an extraordinary period, overseeing our 150th anniversary year, the challenges of the Covid pandemic and countless project wins, challenges and completions.
“Effective immediately, and with our thanks and blessings, Paul will now step away from the business and will be spending more time with his family”
In a later formal statement chairman Ed McAlpine said: “On behalf of the McAlpine Family, I am delighted to welcome Neil Martin to Sir Robert McAlpine in the role of Chief Executive as we move into our 155th year in business and drive forward our “Evolving SRM” strategy.
“Neil brings the essential skills and experience required to lead our business, with a clear focus on project selection and excellence in delivery.”
Martin stepped down as Lendlease Europe CEO 10 months ago, staying on for a further six months to ensure a smooth transition and the process to appoint a new Europe Chief Executive Officer.