Taylor Nelson rejects WPP's latest approach

Taylor Nelson said that the GfK deal still represented better value for shareholders, adding that WPP's continued offers and associated "commentary and innuendo" were an attempt by the world's second biggest advertising company to disrupt the planned merger.

Britain's WPP said it will only pursue the 1.08 billion pound ($2.1 billion) bid if it gets unanimous approval from Taylor Nelson's board.

In an increasingly acrimonious exchange, WPP said it had not had access to additional information that TNS had shared with GfK, "which has meant that WPP has not been able to operate on equal terms to the potential detriment of TNS share owners."

In a strongly worded statement in reply, TNS Chairman Donald Brydon said that his board "has been extraordinarily patient" with WPP chief executive officer Martin Sorrell.

Brydon said that WPP had access to "materially the same information" as GfK, but maintained that their three offers undervalued the company.

"WPP have got all the information they need and have had all the time they need," Brydon said. "It is clear that WPP are determined to try and frustrate the GfK-TNS merger for the benefit of WPP's underperforming Kantar division. It is time for Sir Martin Sorrell and WPP to stop interfering and make their intentions clear."

WPP's cash-and-stock offer values Taylor Nelson at 260 pence ($5.16) a share, based on yesterday's closing price for WPP. That represents a 16 percent premium to Wednesday's closing price for Taylor Nelson and 52 percent to the closing price on April 28, the day before Taylor Nelson and GfK said they were in talks.

Collins Stewart analyst Gareth Thomas said that the offer "represents an excellent deal for TNS shareholders, who, having seen their price propped up by the possibility of a WPP offer, have been spared the collapse of the UK media sector."

"Its difficult to see how TNS can refuse," Thomas added.