It is believed that Labour figures have met Beattie to talk about whether he and BMB can work on social media activity in the last push before next Thursday’s vote.
Labour’s retained agency is Krow. In addition to developing campaign strategy and messaging, Krow has created a number of films and ads, including a poster invoking the Conservative "Double whammy" poster from the 1992 campaign.
Beattie has worked for Labour in a number of guises. While he was chairman and creative director at TBWA\London, Beattie created the merged image of William Hague and Baroness Margaret Thatcher for the 2001 general election.
The Conservatives held talks with regular ad partner M&C Saatchi but no formal relationship materialised.
BMB declined to comment. A spokesman for Labour "categorically" denied Beattie is "coming on board".