Exon only joined RKCR/Y&R in the spring as managing director, after being lured from Bartle Bogle Hegarty where he had spent 13 years.
At the same time, Russell Hopson is promoted from deputy managing director to managing director. Tony Harris moves from international business director to deputy chairman.
Murphy is quitting RCKR/Y&R to form a start-up with Ben Priest, creative director, and David Golding, planning director.
It is understood that parent company WPP Group made a concerted effort to keep the trio at the agency, which is enjoying a spate of success with campaigns for Marks & Spencer and Virgin Atlantic.
The trio's new agency is due to launch in January, when their six-month notice periods come to an end.
Campaign Manager £28-35k Direct Recruitment, London (Central), London (Greater)
Creative Design Manager £35k-£40k per annum + benefits McKay Williamson, London (West), London (Greater)
Flame Artist - Visual Effects Negotiable Sky, London