Other agency workers are permanent employees of the employment agency, directly employed by the agency and sent to work for different businesses.
The only way to be certain about your employment status is to look at your contract terms. If things are not clear, ask your union rep if you have one, or Citizens’ Advice. Your contract terms can include not just the written documentation you have been given by the agency but also other evidence such as emails or evidence showing the way you work.
In most cases, the most important document that will decide whether you are a temporary agency worker or an employee will be the written agreement you have signed with the agency.
Employees have stronger rights than agency workers, including a right not to be unfairly dismissed, and to a redundancy payment where you have at least two years' service.