Mother, which recently lost its £50m Orange mobile phone account, is the agency tipped to have been briefed by Unilever to work on a project for the tea brand although it denied the move.
Overall spend on the PG Tips account is thought to be worth around £10m.
PG Tips was the first tea brand to develop TV advertising with its famous chimp ads, which first appeared in 1956, and went on to become Britain's longest running TV ad campaign.
The chimp campaign was created by Davidson Pearce Berry and continued by DDB after it bought the agency.
The brand changed tack in 2002 when it finally ditched the talking chimps in favour of four animated birds in an effort to attract younger audiences. The T-Birds were created by 'Wallace & Gromit' animation firm Aardman Animations.
The T-Birds were back again last year in a campaign to mark the 75th anniversary of PG Tips with a new campaign also created by DDB.
The brand later backed its association with the new 'Wallace & Gromit' feature-length film with a major web push.
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