Witherall comes from running his own consultancy, The Consumer Data Consultancy, which he set up in January 2004. Until then, he was client services director at Claritas, having worked his way up the company after joining in 1998.
He will report to Tri-Direct's director of data Barry Leeson-Earle, who praised Witherall's "industry credibility".
"As an integral part of the agency's core offerings, I'm keen to develop additional data services and products, which will have an enormous and beneficial effect on our clients' businesses," Witherall said.
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