TUPE rules mean employees principally employed on one account may have financial and legal recourse should they lose their job if the account moves agency.
The warning follows an employment tribunal decision on a claim by Karis Hunt, a PR executive, which indicates responsibility under TUPE may lie with the winning agency.
Hunt worked for Storm PR, where she spent 70 per cent of her time working on a single account. The client transferred to a new agency, Wild Card PR, which refused to take her on. As a result, Storm terminated her employment.
Hunt sued Storm, Wild Card and the client for unfair dismissal, and claimed that her employment should automatically have transferred from Storm to Wild Card. The tribunal ruled that the new agency, Wild Card, was her employer.
Kevin Charles, the IPA's employment law adviser, said: "This should alert the industry to the importance of TUPE."