Czarnowski joined the consumer panel division of TNS in 1993, where he was global account director for Unilever. He went on to run Worldpanel UK and was a member of the Worldpanel Global Board. He joined UK custom at the beginning of 2007.
In his new role Czarnowski will be responsible for driving growth and exploiting TNS's capabilities in the research fields of shopper as well as brand and communications.
He succeeds Richards, who takes on the role of chairman of the UK custom business, in addition to further European responsibilities, including interim responsibility for TNS in Northern Europe and the Baltic States.
Richards has worked in the market research industry for 30 years, firstly at Research International and then at BMRB. He joined TNS in 1993 where he ran TNS Australia.
Richards said: "Andrew will bring strong management skills and some fresh new thinking to the UK business.
"His considerable experience in making research actionable for clients has been instrumental in driving the success of our Custom divisions in the UK and I am delighted about his appointment."