InBev is gearing up to review the premium lager brand Stella Artois' global account, held by Lowe Worldwide.
Although the brewer denied an official process had begun, it is understood to have put Lowe on three months' notice.
The move could bring to an end one of the longest and most fruitful creative partnerships in UK advertising history. Since it launched with the account in 1981, Lowe has created some of the world's most memorable ads, including "pilot", "last orders", "doctor" and "red shoes".
Richard Evans, the InBev vice-president of brands, admitted the company was having conversations with Lowe London regarding changes at the agency.
However, he added: "We have had no official conversations that I know of with any other agencies about the global account."
Lowe London would not deny a review was taking place. Agency sources concur that a decision has been taken to call a review of the global account. The move would fit with InBev's stated global expansion drive and would put the roster networks Leo Burnett and Bartle Bogle Hegarty in a strong position to pitch.
These networks, Saatchi & Saatchi and the US agency McGarry Bowen pitched for InBev's Brahma brand, which it is looking to position as "the world's first global beer".