GfK, the German market research group, on Wednesday said it was “actively pursuing” an alternative all-cash offer for Taylor Nelson Sofres, with financial backing from a third party, in response to a hostile £1.1bn hostile cash-and-shares bid from WPP announced earlier in the day.

GfK and TNS said they would terminate their earlier proposed nil-premium merger. TNS has formally rejected WPP’s offer and has permitted GfK to advance its discussions for an alternative proposal.