A user is pre-qualified for a service provided at a particular location. Location data indicative of where the service is to be triggered and a service element are stored. The service instance element is a full customised instance of the service delivery code or other item that provides an association between the user and an instance of the service for which the user is qualified. The user location, as indicated by a mobile entity associated with the user, is periodically checked against the location data. When a location match occurs, the service instance for which the user has been qualified is executed to deliver the required service to the user. An example is an airline traveler buying, from a travel agent, an air ticket having an associated service wherein, the traveler, upon arriving at the relevant airport, is contacted via its mobile device and guided through check-in and boarding.