The European Patent Office Linked Open European Patent Data Service publishes information about European patent applications using a technique known as Linked Data. This service supports a powerful web interface that can be used by developers to query patent data and retrieve it in a format of their choice. As well as information about patents, this system contains a Linked Data representation of the Cooperative Patent Classification (CPC) scheme. Working in partnership with service providers we helped to undertake data modelling, design and develop the service.