Channel Five has announced the relaunch of its Five Download TV-on-demand service.

The channel has teamed up with BT to compete more aggressively in the growing and competitive TV-on-demand market.

Content will be available as a mixture of online streamed ad-funded and offline download models, including popular shows such as CSI and Grey's Anatomy.

According to Five, the new platform will also include a powerful search engine and simpler payment systems.

"Five Download has already proven very popular and we want to build up the content store to offer viewers even more choice," said Paul Thornton-Jones, digital controller of video and technology at Channel Five.

"To deliver that range of programmes we needed a more advanced online system and by working with BT we are guaranteed just that. This project is key to the success of our online content strategy."

BT has promised that the service will include high levels of encryption and security to help protect customers and content from misuse or piracy.

"TV-on-demand is becoming an increasing priority for broadcasters, enabling them to maximise the value of their content and extend their brand online," said Mark Wilson-Dunn, global vice president for sales and marketing at BT Media & Broadcast.