1. A method of charging in a communications network in which a plurality of charging and enforcement (CaR) components operate as enforcement points for a single data communication, comprising: receiving one or more usage records from a first CaR component of the plurality of CaE components that operate as enforcement points for the single data communication; receiving one or more usage records from a second CaE component of the plurality of CaE components that operate as enforcement points for the single data communication; generating correlated usage records by using a common Service Data Flow (SDF) to correlate the one or more usage records received from the first CaE component with the one or more usage records received from the second CaE component; and using the correlated usage records to determine a charge value that identifies correct charges to be applied.