Hamer will be joining the £900m turnover family-owned contractor at the end of next month after more than eight years at the top of WYG, where he turned around the fortunes of the publicly-listed consultancy.

He replaces Tony Aikenhead who stepped down last July after just eight months as the first non-family chief executive of the McAlpine business.

WYG also today announced that former Sweett CEO, Douglas McCormick, will take over from Hamer when he leaves the group.

Hamer led WYG through two major financial restructurings in 2009/10 and 2011, returning the consultant to profitability, and a period of significant growth.

His previous roles include director of projects at BNFL Environmental Services where he was responsible for the decommissioning of all the UK’s civil nuclear sites, and director for projects with Costain.

He joins after Sir Robert McAlpine edged back into the black last year after suffering a major combined operating loss of £128m in the previous two years.

The McAlpine family has set a target of generating a major part of its turnover from civil engineering by the end of 2019.

Gavin McAlpine, non-executive chairman of Sir Robert McAlpine, said that Hamer brought a proven track record for delivery, both as a client and as a contractor.

“At WYG, Paul refocused the business around driving value for its clients.

“At Sir Robert McAlpine, we are focussed on our clients’ needs and delivering exceptional value.

“I am certain that Paul will challenge us all to excel in supporting these objectives. We are looking forward to working in partnership with Paul for the next phase of Sir Robert McAlpine’s evolution.”

Hamer said: “I am delighted to be joining Sir Robert McAlpine as it approaches its milestone anniversary of 150 years in business.

“We will be building on the key strength of engineering excellence while leveraging the tradition and heritage of this great company. We aim to enhance our focus on our clients and their needs whilst ensuring that we deliver excellence in all of our operations.”