Baker spent more than 12 years in the TV trading arena, starting his career at ITV within its sales house TSMS in 1994. He then moved to Initiative, where he spent 10 years before moving on to become head of TV trading at Interpublic Group's Brand Connection.
Ditcham said: "Richard has a first-class understanding of the television marketplace and his appointment will further strengthen the office."
The position of independent adjudicator, with responsibility for the contract rights renewal mechanism, which stops ITV abusing its power, went to Ditcham in April this year.
He was formerly commercial director at Initiative and replaced David Connolly, who left after two-and-a-half years at Ofcom.
Prior to being appointed commercial director at Initiative, Ditcham was a broadcast director at the agency and also launch director of TV network Rapture. He left Initiative in June 2005 as part of a restructure.
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