Sir Martin Sorrell has “strenuously” denied paying for a sex worker using funds from WPP, the company he founded and developed into the world’s largest advertising group.

The remarks follow a report in the Wall Street Journal on Saturday, which claimed one of the matters the investigation into Sorrell had examined was whether he had used company money for a sex worker. The findings of the investigation have never been made public.

The comments come eight weeks after the tycoon resigned as chief executive of the company, a departure that was announced before the conclusion of an investigation into alleged personal misconduct made against Sorrell.

Sorrell’s spokesman said on Sunday: “Sir Martin signed a non-disclosure agreement when he stepped down which precludes him from discussing any of the circumstances surrounding his departure. He has rigidly adhered to this obligation and will continue to do so.

“As regards the allegations which have appeared in the Wall Street Journal, Sir Martin strenuously denies them. He will be making no further comment at this time.”

For WPP, Sorrell really is the hardest word Read more

A spokesman for WPP said: “WPP has been advised that it cannot disclose details of the allegations against Sir Martin Sorrell because it is prohibited by data protection law from giving such details. Sir Martin chose to resign at the conclusion of the investigation by independent legal counsel.”

The latest development in the saga emerged as the advertising group is set to host its annual general meeting this week. The company is braced for a tough reception from shareholders, who are agitated about executive pay and how the board planned for the departure of the 73-year-old Sorrell, as well as the detail surrounding his exit.

Pirc, a consultancy firm that advises shareholders on how they should vote at AGMs, recommends that WPP shareholders reject the first resolution on Wednesday’s agenda to “receive” the whole annual report.

It said: “There is no disclosure regarding the reason for the sudden departure of the group chief executive. Shareholders should be informed of significant company events such as this. Due to the lack of transparency, an oppose vote is recommended.”

Another advisory firm, Glass Lewis, added: “Absent [sic] further information, it’s a bit unclear as to whether treating Sir Martin as a ‘good leaver’ is appropriate and the board may face tough questions regarding their ‘oversight’ of the situation, along with succession planning.”

Sorrell, who was the longest-serving FTSE 100 chief executive until his departure, was paid £13.9m in 2017, £48.1m in 2016 and £70.4m in 2015. He is set to receive further payments related to 1.6m shares in a number of award plans that will vest over the next five years. The exact value depends on the company’s performance but at WPP’s current share price the awards are worth about £19m.

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WPP employs more than 200,000 staff in 400 separate advertising businesses working in more than 3,000 offices in 112 countries.

It began its transformation into the world’s largest advertising group after Sorrell, who had been the finance director for the advertising agency Saatchi & Saatchi, acquired a small Kent-based maker of wire baskets called Wire and Plastic Products in 1985. The company was then used as a vehicle to make a series of acquisitions, including J Walter Thompson Group for $566m in 1987 and the Ogilvy Group for $864m in 1989.

Roberto Quarta, the WPP chairman, has taken the role of executive chairman until a replacement for Sorrell can be found. The company has appointed two longstanding WPP executives from ad group Wunderman – Mark Read and Andrew Scott – as joint chief operating officers to run day-to-day operations. WPP has said that Sorrell would be “available to assist with the transition” to a new chief executive.