This Practice Note considers the regulation of the resale of mobile voice services, with a particular focus on the UK market. Resale normally takes place when a smaller mobile operator buys services from a larger operator which has been allocated a range of spectrum, and the smaller operator then resells those services in the market. In this scenario, the end customer normally has no contact with the underlying mobile operator and as far as the customer is concerned, its relationship is with the smaller operator and it is the smaller operator that provides the service.