Lost Witness is the English trance producer and DJ Simon Paul (also known as Si Paul), working in collaboration with songwriter Edward Barton, writer of the 1983 Jane & Barton single, "It's a Fine Day" (later covered by Opus III in 1992), and vocalist Danielle Alexander.

He also recorded under the aliases Dusk Til Dawn and The Eden Project.

A number of their singles co-written and produced by Simon Kemper were released on major electronic dance label Ministry of Sound. Some included remixes by English producer and DJ Lange. The 2002 single "Did I Dream (Song to the Siren)" is a cover of the frequently-covered "Song of the Siren" from the 1970 Tim Buckley album Starsailor.

In 2010, Lost Witness re-released the 1999 single "Red Sun Rising" (with vocals from Andrea Britton). It was given airplay by BBC Radio 1 DJ, Judge Jules. A new single, "Fade Away", was released in 2011. In June 2013, they collaborated with Sugababe and former Eurovision entrant Jade Ewen to release the track "Fly".