The giant consultant said it would merge its six operating businesses into four market-focused divisions over the next six months.

Nick Roberts, who is currently strategy and growth director for Atkins’ North America, will replace Tonkin.

Atkins said the UK business shake-up was being made against a backdrop of increasingly complex challenges, continued pressure on budgets, industry consolidation and a growing shortage of people with the right skills

It said the shake-up would allow it to provide higher levels of certainty and flexibility of skills to its clients.

Atkins said it could not rule out job losses with the final numbers due to be decided over the coming months.

A spokesman said any staff made redundant could be redeployed in other areas because Atkins currently has more than 1,000 vacancies to fill across the group.

There will be no changes to Faithful+Gould or Atkins’ Energy division in the UK.

Prof Dr Uwe Krueger, chief executive officer, Atkins, said: “As our clients and markets evolve, so must we.

“These changes position us better to deliver the technical capabilities, resources and innovation that will help our clients meet their business goals and solve the increasingly complex challenges we face.”

The firm said David Tonkin, who has been UK chief executive since 2010, had decided to step down from his role as UK & Europe chief executive officer to focus on the health and wellbeing of his family.

The transition to the new operating model will be completed by 1 April 2015. Nick Roberts will assume his post on 1 December 2014.