Capita offers IT-based services to public and private sector companies so they can cut costs, but has given a series of profit warnings after delays in spending decisions following Britain's vote to leave the European Union. It has increasingly struggled to manage a diverse spread of activities following years of acquisitions.

"You can't be effective at applying technology unless you have a really deep understanding of your customers' business model, and Capita has that understanding perhaps better than many. That's a little bit of the secret sauce at Capita," he told Reuters.

Lewis, who is 55 and has two children, takes up his post on Dec. 1.

Capita has also suffered from a lack of clear communication and Lewis said his style was candid and inclusive.

"I think if you talk to a lot of past employees at Amec Foster Wheeler they will tell you that I took many of their views on board before deciding on the long term strategy," he said.

(Reporting by Elisabeth O'Leary; editing by Stephen Addison)