British military aircraft designations are used to refer to aircraft types and variants operated by the armed forces of the United Kingdom. Since the end of the First World War, aircraft types in British military service have generally been known by a service name (e.g. "Spitfire"), with individual variants recognised by mark numbers often in combination with a letter to indicate the role. This is in contrast to identification systems used in countries such as the United States, where an aircraft type is primarily identified by an alphanumeric designation.