The appointment will surprise many in the industry, as WPP's Mediaedge:cia was hotly tipped to land the business after it won BT's media planning account last August.
Starcom retains media buying duties, while adding media planning. Zed Media, part of the ZenithOptimedia Group, will retain online buying.
The pitch, which was called by BT's head of media, Steve Huddleston, in October, was hotly contested. MEC, backed by the buying clout of Group M, seemed to gain the early momentum. However, senior figures in the BT marketing department are said to have been impressed by the Publicis approach and its ability to match Group M on price.
Starcom's relationship with BT extends almost six years to when it landed the press buying business. In 2005, it won the TV buying brief from the now defunct The Allmond Partnership. Zed has worked with BT since August 2005, when it won the online brief after i-level resigned the account.
The loss of the planning brief comes just months after MEC hired the former PHD director and planner Stuart Bowden to run the business. He had previously worked in-house for BT on its media planning.