In London Borough of Camden v Pegg the EAT decided that an agency worker could rely on the contract worker provisions in the Disability Discrimination Act (which are largely the same in the Equality Act which has replaced it) to bring a disability discrimination claim against the end-user. 

Agency workers are not usually employed by the end-user but the discrimination legislation allows for this and they are protected under the "contract worker" provisions if they are "employed" (under the discrimination definition, which is wider than the one that applies for general employment rights) by another person (the agency) and supplied to the end-user (the "principal") under a contract. 

The claimant, a specialist in school travel planning, had a contract for services with the agency.  She was not obliged to accept an assignment, but if she did so she was contractually obliged to the agency personally to do work for the end-user.  She was placed (via a second agency) on an assignment with Camden, where she was fully integrated with other members of staff.  When the assignment terminated nearly a year later she brought a disability discrimination claim against Camden.

The EAT upheld the tribunal's decision that the claim could proceed.  Under the contract with the agency the claimant was obliged to perform work personally in relation to assignments.  She was therefore "employed" by the agency.  She was supplied to Camden under a contract with the agency and Camden provided work for her to do. Camden was therefore a "principal" and the claimant was a contract worker.

It had been thought that agency workers might not be able to bring themselves within the contract worker definition, because of a controversial 2010 Court of Appeal decision, Muschett v HM Prison Service, which suggested that an agency worker was not employed by the agency because he did not have an obligation to provide personal services for the agency.  Although Muschett was not referred to in Pegg, it was regarded as a slightly surprising decision at the time and this case confirms what had previously been understood to be the correct interpretation.