Cooper is responsible for travel, Lebond for sales promotion, Sylvester for motivation and Hocken is finance director.
"The business will carry on as normal but run as a partnership with each director having an equal say,
said Cooper. "We have all taken on slightly more responsibility to cope with David's departure but that is all.
Cooper added that Basham did not leave to join another agency and would not be returning to P&MM.
"We are also working more closely with our non-executive group chairman David Hill. He will now become the figurehead of the business, as Basham was,
P&MM has also just released its first quarter financial results. Cooper said: "We are 50% up on last year in the travel and events department and the agency as a whole is 20% up on 2001.
"Post 11 September we lost around £500,000 in business, but most of that was rebooked for the beginning of this year. We are £1m up on this time last year and are forecasting a record year for profits. Just one of our recent account wins on the motivation side was worth £4m,
P&MM has just completed a major product launch for Range Rover and Cooper said two more launches of a similar nature are planned for later in the year.