WPP has confirmed a senior management restructure at Group M, the UK's largest combined media buying operation, promoting Stephen Allan to a worldwide role with Nick Theakstone stepping up to run the UK operation.

Allan, made head of Group M UK in 2005 after WPP acquired media agency MediaCom, has been named chairman and chief executive of MediaCom Worldwide.

As a result Theakstone, chief operating officer at Group M UK and Allan's number two, has been promoted to chief executive with immediate effect.

Theakstone will be responsible for managing the UK's largest media buying group, which combines the media firepower of agencies MediaCom, MindShare, Mediaedge:cia, BJKE and Maxus.

Allan succeeds Alexander Schmidt-Vogel, who has taken on the newly established role of chief executive global trading of Group M Worldwide.

The management restructure was triggered by a recent decision by Schmidt-Vogel, 59, to move on to a new phase in his career.

Allan, who had previously spent five years as UK chief executive of MediaCom, was seen as the obvious internal choice as his replacement.

"Stephen has invested his heart in the MediaCom and Group M networks over the years," said Irwin Gotlieb, the chief executive of Group M.

"When the opportunity came up for him to continue shaping and growing the business in a significant potent manner, he jumped at the chance," Gotlieb added.

Group M is Sir Martin Sorrell's powerhouse media buying operation, accounting for around 30% of total UK ad spend through its various agencies. WPP uses this clout to leverage better deals with media owners on behalf of advertisers.

The combined agency operation has annual advertising billings in excess of £2.46bn in the UK.

Theakstone said that Group M's job was to "support" WPP's media agency operations.

"We have a fantastic team at Group M and all look forward to supporting the media agencies, in order to enhance their market deliverables and position as well as looking at all forms of new business opportunities," he added.

"I feel extremely privileged to work with the best agencies and media experts in the UK, and look forward to continued success for all our companies."

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