Chris Martin, the executive creative director, and Tim Lines, the deputy creative director, are to leave the agency. Their plans are unconfirmed, although it is thought they will be working as a freelance creative team.
The pair were recruited by Marcus Evans shortly after he joined Carlson in November 1999. All three had previously worked for Bates Communications.
The departure is said to be an amicable one, with the duo planning to help the Carlson boss, Frank McCusker, in his search for their replacements.
The departure will come as a blow to Carlson, which parted company with its senior management team earlier this year. The UK chairman, Evans, the managing director, Steve Grout, and the group creative services director, Nick Burton, all left the agency in April.
Carlson explained their departures as the result of a management restructure, although some industry sources claimed the move was fuelled by a difference of opinion over the direction the agency was taking. The day-to-day running of the agency has passed to McCusker, the managing director of Carlson's Northampton office.
Grout has since returned to WWAV Rapp Collins as the head of international, while Evans is rumoured to be on the verge of launching a start-up agency.
Martin denied that his departure had anything to do with Evans, although he did not rule out the possibility of one day working with him again.
Martin said: "The leaving is very amicable - we'll probably still consider doing some consulting for Carlson in the shorter term and we're being retained by them on a couple of other strategic projects.
"But we've had enough of the big corporate stuff. We want to get back to where creative counts and to where the work counts. At the moment, we're going to just go and lie on a bedroom floor and do some creative work."