But there might yet be a tug-of-war between WPP and Publicis. Despite reports that the French group was withdrawing from the contest, a source in Paris warned: "Don't write us off yet."
Sorrell and his Publicis counterpart, Maurice Levy, met on Thursday last week to discuss their respective bids amid growing shareholder anger about the severance payments due to Cordiant's chief executive, David Hearn, and the finance director, Andy Boland, if and when the group is sold.
Under the agreement Hearn and Boland could leave with more than £1.5 million and more than £580,000 respectively.
"They get paid for selling the company while everybody else gets stuffed," a shareholder representative said. "Why should anybody take this industry seriously when this kind of thing happens."
Meanwhile, if WPP's bid is successful, it would be obliged to sell Cordiant's 25 per cent stake in ZenithOptimedia to Publicis, giving it 100 per cent control. Publicis has a right to buy Cordiant's stake at a pre-set price of £75 million.
However, any deal would be complicated by the fact that ZenithOptimedia operations in Hong Kong, IndoChina, Malaysia and Argentina are wholly owned by Cordiant with the brand name used under a franchise arrangement.