Dutch firm MediaMonks has been acquired by Sir Martin Sorrell’s S4 Capital for €300m (£265m), with the former chief executive of WPP beating out his ex-employer in a move designed to return him to the forefront of the ad industry, less than three months after he stepped down amid allegations of misconduct.

S4 Capital proceeded with the deal despite Sorrell having received a letter from WPP alleging that doing so was “unlawful” and in breach of his confidentiality agreement with the firm. WPP claim that Sorrell had already looked into buying the digital ad production firm when he was still chief executive at the company, although Sorrell denies this.

Sorrell was forced out of WPP, a firm he founded, in April following an investigation into allegations of personal misconduct, abuse of company resources and improper behaviour. Sorrell has strenuously denied the allegations. He created S4 Capital less than a month following his exit from WPP, and swiftly took part in a reverse takeover, where the company was acquired by shell company Derriston Capital, which proceeded to rebrand as S4 Capital.

“This represents a significant step in building a new age, new era, digital agency platform for clients,” said Sorrell, who has taken the title of ‘senior monk’ at MediaMonks. “MediaMonks’ roots are totally in new media, and data, content and technology. Our next moves will be to build this platform further and to add meaningful data analytics and digital media buying. The company will be a unitary one with MediaMonks as its core.”

MediaMonks boasts offices across the globe, including London, New York, Dubai, Shanghai and Singapore, and its clients include Adidas, Shell, Audi, Google, Netflix, GE, Amazon and Lego.