The creative director Garry Walton is taking action in the High Court against the US owners of the London agency he helped them buy.
Walton, who has issued a writ alleging constructive dismissal against Earl Palmer Brown, cites 'intolerable pressure' as the reason for his departure as executive creative director of EPB's London operation in early December.
The departure of Walton, a founding partner of Walton & Wiggins agency and a Cannes Grand Prix winner, follows what he claims was the reneging by EPB on a promise to assign him shares in the privately owned corporation after he helped it purchase the agency - then called The Square - from the recruitment specialist TMP.
In a statement issued through his solicitors, Izod Evans, Walton said: 'The company failed to give me shares that I was entitled to in my contract, demanded that I transfer back shares I held in the company and then threatened to fire me over the issue. I could not continue to work for them with that threat hanging over me.'
The legal row is the latest in a series of troubles to hit the London agency since EPB acquired it in September 1998. Its 40-strong staff has since been halved in numbers and it has also lost its biggest client, Peugeot, for which it handled the fleet, contract hire and commercial vehicle accounts.
Calls to the New York office of Jeb Brown, EPB's group chief executive, asking for comment on Walton's action were not returned.