Campbell leaves Rainey Kelly Campbell Roalfe/Y&R - the agency he founded ten years ago - to become McCann's UK executive creative director and the vice-president creative for Europe, the Middle East and Africa. His UK predecessor, Luke White, loses the "executive" from his title, but stays on as the creative director.
Price will work with the chief financial officer, Craig Denyer, and the head of HR, Barry Richards, to improve the agency's legal, financial, IT and personnel infrastructure.
His appointment sees him reunited with Howell, with whom he set up Howell Henry Chaldecott Lury in 1987. He also worked with Howell at Chime Communications and was his partner in The Growth Organisation, the consultancy they closed in June just three months after launch.
Campbell and Price are the first major appointments Howell has made since he landed the job of McCann UK & Ireland chairman and president EMEA in September. With the UK chief executive, Chris Hunton, the three will seek to provide McCann with the stability it has lacked over the past two years.
The trio's first task is to stem the tide of account reviews being called by McCann clients. Coca-Cola and Somerfield have both recently parted company with the agency, while its Bacardi Breezer and Birds Eye accounts are still being contested.
Howell said: "My brief was to put together a superstar team - running an agency like McCann is not a job for twentysomethings.
"It is an agency that has been out of balance. Historically, account handling has ruled the roost, but it has not been investing in creative leadership. I have known Robert for 15 years and I knew from the outset that he was the one I wanted to work with.
"Robin has been my business partner for 15 years and is acknowledged to be the leading commercial professional in the UK communications business."
Campbell said: "I was looking for a new challenge, and the chance to join Rupert and turn McCann into a leader in London proved irresistible. The client list is to die for, the scale extraordinary and the opportunity immense."
Campbell's departure coincides with a restructure of the RKCR/Y&R management team which sees the joint chief executive MT Rainey promoted to chairman, leaving the fellow founder Jim Kelly to take sole charge of the chief executive position. Mark Roalfe, Campbell's partner of 23 years, becomes the executive creative director.
William Eccleshare, the chairman of Y&R/Wunderman Europe, said: "I'm delighted MT, Jim and Mark have decided to continue to drive their agency to greater heights."
He added that the agency was sorry to lose Campbell.