Saatchi & Saatchi is seeking an injunction against its founder and three top executives who quit to set up a rival firm. They are accused of conspiring to damage its business.
Mr Saatchi, Jeremy Sinclair, the former deputy chairman, and the ex-heads of the Saatchi & Saatchi Agency Worldwide, Bill Muirhead and David Kershaw, were not in court.
A Saatchi & Saatchi spokesman said fresh writs were served yesterday seeking to widen the terms of the injunction in a bid to stop the team from poaching staff under any circumstances. Key figures on some big accounts are among staff who have quit in sympathy with Maurice Saatchi. He was fired as chairman in December after a shareholder revolt, and walked out at the start of January after turning down a lesser role.
Saatchi was set up by Maurice and his elder brother Charles a quarter of a century ago, and became the world's biggest advertising firm in the 1980s.
As part of yesterday's hearing, Saatchi & Saatchi accused Mr Saatchi of soliciting his three colleagues for the "New Saatchi Agency" he is setting up. Maurice Saatchi has already replied with a writ of his own, claiming Saatchi broke his contract when itfired him.
Although Mr Saatchi was fired and is therefore entitled to compensation - negotiations on his severance package are under way - Saatchi says the others are still technically employees and bound by clauses in their contracts that stop them from working for rival operations.
"If the judge finds for us we expect a full trial to come to court this year," a Saatchi spokesman said. Saatchi will seek "substantial" damages if that happens, but a court case could drag on for years.
The proceedings continue today.