It is hoped the initiative, which was instigated by the company's chief executive, Ben Verwaayen, will yield one clear branding device that can be used across all of BT's services, from fixed-line telephony to business-to-business communications to its 118 500 directory inquiries service.
Fallon, St Luke's and Abbott Mead Vickers BBDO are each developing one overarching idea that can travel across BT's £100 million above-the-line communications budget. The winning idea will then be used and adapted by all of BT's roster shops.
BT feels a consistent advertising message would be more effective than its disparate existing campaigns.
CHI won a place on BT's roster at the beginning of the year. However, its work for Carphone Warehouse and British Gas, both of which operate fixed-line services, now present a significant client conflict with BT.
Until now, the agency was able to handle the £10 million BT Yahoo! account as it presented little conflict with BT's fixed-line competitors. However, BT's new initiative to promote a centralised communications message means that CHI could no longer be partitioned off from BT's fixed-line operation.
BT and CHI have now reached a mutual understanding that their relationship cannot progress beyond next March.
Amanda Mackenzie, the director of marketing services at BT, explained it was "fundamentally" a conflict issue. She said: "It hasn't been an issue until now, but we are anticipating that it will be in the future. We had always split out our fixed-line business but now all of our agencies need to be able to do that."
She added: "More and more of what we are doing is about coming together. More and more often there will be one BT approach."
She explained that the vast size of the advertising account meant she was not looking to centralise into one agency. "We will manage the roster in a more focused way, but we won't change it," she said.
"I think incredibly highly of CHI and have a great roster of talent in the other agencies," she added.
The attempt to invent an overarching strategy harks back to the success of BT's "it's good to talk" campaign starring Bob Hoskins.
The idea yielded by the pitch may be an endline or another mechanic, such as a graphic style, that could be mandated across all of BT's agencies and communications.