Employers should note that agency workers may be able to bring whistleblowing claims against both the end-user and the third party introducer. The fact that an individual is a worker for one party does not inevitably prevent them from also being a worker (under the extended definition for whistleblowing purposes) for another party. The Court of Appeal has agreed with an earlier EAT ruling (McTigue, summarised in our blog post here) that an agency worker can be a 'worker' for whistleblowing purposes for both end-user and agency, where between them they have 'substantially determined' the worker's terms. (Day v Health Education England)
Given that employers can face whistleblowing claims from agency workers supplied to work in their business, it may be prudent to review and update whistleblowing policies to cover agency workers, possibly to allow them to use internal channels, but also to ensure employees know not to retaliate against agency worker whistleblowers. End-users who decide no longer to use an agency worker who has blown the whistle should ensure they have documentary proof of genuine reasons unconnected with the whistleblowing.