Hamer, currently the firm's chief operating officer, becomes group managing director. He will report to chairman Peter Wood, who, as a consequence of these changes, will increase his time in the business.
White Young Green has been the subject of persistent takeover talks since being named NCE/ACE Major Consultant of the Year in March and has seen its share price drop by more than 70% in the last year to a four-year low. Its net debt has grown from £15M in 2005 to £68M.
In an interim management statement in November it confirmed that trading was poor and was cuttting £5M in costs, £4M of which coming from redundancies in those areas of the business experiencing reduced demand. Other staff were being redeployed into more buoyant areas within the public sector such as healthcare, education and infrastructure.
Analysts said the change had to be made: "The company has done the right thing, but it has still got to do a lot more on cost reduction, and by that I mean people," said Numis director Francesca Raleigh.
"The company has made a lot of acquistions that are not properly integrated and it has got to remotivate its people."
Commenting on the changes, Wood said: "Over the last few months White Young Green's priorities have changed in response to the challenging economic environment.
"Whilst our primary responsibilities remain to ensure that we continue to deliver high quality services to all our clients, we now also need to ensure the business is in the right shape to exploit the recovery when it arises.
"We will have a more efficient cost base and our business model will be focused on the key commercial growth areas as outlined in our business strategy. The Board believes the changes we are making today underpin that strategy.
"I would like to thank Lawrie Haynes for the contribution he has made to the Group over the past 18 months."
Paul Hamer has over 20 years experience in business management, leadership and project delivery across the nuclear, oil, gas, petrochemical and pharmaceutical industries. Previous employers include British Nuclear Group, BNFL, Costain Oil and Mowlem Engineering Ltd.
Haynes joined White Young Green in June 2007 from British Nuclear Fuels. Over the years, he has held a number of leadership positions with a range of blue chip organisations including Lattice Group, PriceWaterhouseCoopers, the Highways Agency and British Aerospace.