The news comes three weeks after AMV was forced to resign its £20m Yell ad account, which it had held for 23 years, because of conflict with BT. Yell also asked PHD to drop one of the accounts.
The deal was agreed between AMV and PHD as a way to keep both the BT and Yell businesses within Omnicom.
It is thought that a BT team will be set up within AMV to run the entire media planning business. PHD staff working on the BT account will be offered positions on the newly formed team within the creative agency.
Yell, the £20m-spending directory company, feared conflict with BT following the telecoms provider's decision to move into the directory market at the end of last year.
Yell, whose portfolio includes Yellow Pages, Business Pages, Yell.com and the directory enquiries service 118 500, was originally part of BT's classified directory service.
BT's media buying, which is handled by Starcom, is unaffected by the move.
Neither Yell nor BT were prepared to comment.
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