At the same time, Sir Martin Sorrell, chief executive of WPP, is said to be considering taking the Takeover Panel to a judicial review.
Yesterday, the full board of the Takeover Panel said that it was rejecting WPP's argument that it should be allowed to back out of its £432m bid for Tempus by invoking the material adverse change clause. The panel is due to publish its reasons for the decision on Monday, at which point WPP will have 24 hours to appeal again.
Tempus is keen for WPP to accept the deal and end the uncertainty over its future. The threatened walk-out by Ingram would be a damaging blow for WPP.
The dispute has led to much speculation about how Ingram and Sir Martin would work together after the takeover has gone through. Ingram told the Daily Telegraph, "I would expect to sit down and discuss any further role I might have in the enlarged group and consider my options."
While watching the battle between the two media companies with morbid interest, the City does not seem overly concerned with the outcome, arguing that Tempus will be such a good fit in the WPP Group that paying the full £432m for the company will not hurt Sir Martin too badly.
Shares in WPP were trading up this morning by 2.8% at 642.5p.
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