In the past 20 years Healthlink has expanded from a single hospital proof-of-concept to a national broker for country-wide messaging with over 18 million exchanges of information annually. Healthlink messaging is at the core of the National Electronic General Referral Project, the National Cancer Control Programme referral initiatives and GP communication from the National Screening Service. Alongside national projects, Healthlink transfers a range of messages in real time including laboratory and radiology reports, discharge information and waiting list updates. Message files are specified in HL7, an internationally recognised standard for healthcare information exchange and formatted in XML. The system interfaces with hospitals, clinical centres, healthcare agencies and GP practice management systems and transfers data via a secure network to its messaging servers. The HealthlinkOnline portal is secured with SSL and Client Certificates. Web Services are also made available as an alternative access to our system and for best interoperability.