Abstract: This invention relates to a method of authenticating subscription to a mobile content service. Currently, the known methods of authenticating subscription to a mobile content service are unsatisfactory due to their susceptibility to fraud and their complexity. The present invention obviates the problems with the known methods by introducing a third party Unique Identifier verifier 7 (TPV). The TPV 7 generates a Unique Identifier code on request of a service provider 5 (SP) and transmits the Unique Identifier code to a mobile communication device 9 (MCD). The MCD 9 then transmits this Unique Identifier code to the SP 5 who in turn verifies the Unique Identifier code with the TPV 7. If the TPV 7 verifies that the Unique Identifier code is authentic, the MCD 9 user is subscribed to the service. This method simplifies the existing methods and furthermore reduces the possibility of fraud.