Tetley originally appointed D'Arcy to its account in 1979 and it was one of several accounts that switched to Leo Burnett when the agency was closed by parent company Publicis Groupe in 2002.
Tetley confirmed it is to review the account but said the review was at an early stage.
A spokesperson for Tetley said: "We're reviewing our choice of agencies. We have had a long and successful relationship with Leo Burnett but it is time for a change and to look for fresh ideas."
The account was worth 拢15m in 2002 when the brand was relaunched but current spend is estimated to be between 拢5m and 拢10m.
D'Arcy developed a string of campaigns built around the Tetley Teafolk, that gentle band of flat-capped Northern workers called Gaffer, Sidney and Maurice who were first introduced in 1973. The agency was also behind the introduction of the famous strapline "that's better, that's Tetley".
But 30 years later Tetley abandoned the cartoon characters that had populated its advertising. In 2001 it put the account up for pitch, saying that it wanted to target a younger audience. D'Arcy retained the work and developed a new strategy, even though it was against abandoning Sidney and his friends.
The dropping of the Tetley Tea Folk certainly won a lot of coverage for the brand. But the campaign that followed, which said that "Tetley is rich in anti-oxidants that can keep your heart healthy", was banned by both the Advertising Standards Authority and the Independent Television Commission for being misleading.
Despite the controversy, the brand has become the market leader in value and volume, according to ACNielsen Scantrack, with a 27% volume share of the UK teabag market compared with PG Tips' 22.5%.
Subsequent work, created by Leo Burnett, used the strapline "Ready Tetley Go". It reverted somewhat to the original them of the comforting properties of Tetley by showing that a cup of tea can help get someone through the toughest situations.
With the rise in sales it is unlikely that the Tetley Teafolk will be brought back any time soon.
The media planning and buying account is held by sister Publicis agency Starcom MediaVest.
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