Mr Saatchi's QC, Gordon Pollock, said his client was also legally able to take clients from his former company to the new business he is setting up, New Saatchi Agency, inflicting losses on his previous camp.
He said the former chairman was entitled "to lure away every single employee" of Saatchi & Saatchi, as long as contractual and post-contractual agreements were upheld.
Maurice, who founded the agency with his brother, Charles, 25 years ago, and helped it mushroom into the world's biggest advertising firm in the 1980s, had been scrupulous not to breach these contracts, Mr Pollock added.
It was the second day of the High Court hearing into an injunction Saatchi & Saatchi seeks against its estranged founder and three top executives who quit to help set up the rival firm after a December shareholder revolt triggered Mr Saatchi's acrimonious departure.
The others are Jeremy Sinclair, former deputy chairman, and Bill Muirhead and David Kershaw, ex-heads of Saatchi & Saatchi Agency Worldwide.
The injunction seeks to stop the four breaking their contracts by illegally soliciting S&S's employees.
Mr Pollock told the court S&S's contention that trade secrets, confidential information and know-how were being passed on by Muirhead, Kershaw and Sinclair relied "on innuendo and speculation to a degree which suggests paranoia has taken root in Mr Saatchi's old company". There was no hard evidence, he added.
Charles Gray, QC for Saatchi & Saatchi, said the departing executives had a clear conflict of interest between their duties to the company and their desire to join Mr Saatchi's new business. They had "crossed the Rubicon" by committing themselves in future to subscribe to shares in New Saatchi Agency. That move, allied to Mr Saatchi going around drumming up business for a group they would join and benefit from, breached their contracts, Mr Gray said.
"Maurice Saatchi is the front man and the other three are doing we don't quite know what in the backroom," Mr Gray added.
The departing trio have maintained in court that they have the right to prepare for their new jobs as long as they don't steal clients or employees. But Mr Gray said it was fanciful to believe they could prepare "behind some sort of Chinese walls" and not get involved in planning business strategy, and how to pitch for rich accounts such as British Airways.
Yesterday's case is seen as a stop-gap legal action by Saatchi & Saatchi pending a full court hearing later this year.
The hearing continues today.Reuse content