Sorrell takes issue with WPP as he wins MediaMonks race

Sir Martin Sorrell has dismissed anger at WPP (Frankfurt: A1J2BZ - news) after his new business venture beat the FTSE 100 advertising giant to buy digital agency MediaMonks.

The 73-year old businessman's S4 Capital confirmed on Tuesday it was to snap up the Dutch company, thought to be worth £265m, for an undisclosed sum.

WPP had warned Sir Martin, who left the company he founded in April as it examined allegations of personal misconduct against him, that his bid was " unlawful" and it could seek to strip him of WPP shares awards worth up to £20m .

It claimed Sir Martin had been "heavily engaged" in its evaluation of the bid for MediaMonks.

Sir Martin, who has insisted there was no merit in the company's misconduct probe, has asked WPP to provide evidence of his involvement in its MediaMonks bid.

He told the Press Association it was "ridiculous" to suggest that S4 was competing head-to-head against WPP.

The businessman said: "We've probably grown from being a peanut to a coconut with MediaMonks.

"We are a bigger animal now, but still to say a 20 billion US dollar company can be frightened of a peanut or a coconut seems to be ridiculous."

His new vehicle, S4 Capital, lined up funding from a consortium of City investors to acquire MediaMonks, which counts Audi (IOB: 0FG8.IL - news) and Lego among its clients.

The shareholders of MediaMonks, which has revenues of £97m, will receive cash and shares in S4 Capital.

S4 Capital has been created from a reverse takeover of Derriston Capital, a listed cash shell. Sir Martin plans to use it as a vehicle to build a "next-generation" marketing services group.

Sir Martin has committed £40m of his own money to the new venture.

His ability to establish a business in direct rivalry with WPP, the owner of J Walter Thompson, Ogilvy and Young & Rubicam, while retaining unvested share options led to a limited shareholder protest against the chairman, Roberto Quarta, at last month's annual general meeting.

Sir Martin remains a significant shareholder in WPP, with much of his wealth tied up in the stock of the company he took from a manufacturer of shopping baskets in 1985 to bestriding the global advertising industry.

By the time he stepped down in April, WPP was valued by the stock market at more than £16bn.

Its shares have slipped in recent months, however, amid investor anxiety about the impact of marketing budget cuts and shifts at major global advertisers.