The scheme will run over 3 years, with 6 distributions per year. Each distribution will contain 1 sample for Campylobacter spp. detection and 2 samples for enumeration. The samples consist of freeze-dried matrices containing Campylobacter. Samples for detection may not always contain Campylobacter, and may also contain other background organisms/microflora. The samples will be homogeneity and stability tested by the Food and Environmental Proficiency Testing Unit (FEPTU) at Public Health England prior to distribution. Transit of the specimens will be temperature logged. The freeze-dried samples will be reconstituted by the participating laboratory according to protocols set by FEPTU, prior to testing by in-house methods. Each participating laboratory will enter their results into a secure website, stating which method has been used for testing. Participants will be scored against a known value/range, and provided with a Z-score and PHE score. The Z-score represents how far the participant’s result deviates from the median value and is commonly used for PT schemes. The PHE score allows the participants to monitor their performance over time. At the end of each distribution, individual laboratories receive a report on their performance for that distribution as well as their performance over all distributions. FEPTU will provide expert advice for participants upon request, and will provide repeat specimens for test failures, to provide training opportunities for participating laboratories.