A French court has said it's unclear what caused a French trawler to sink over a decade ago off the British coast, killing five people.

The entire crew of the Bugaled Breizh drowned when it capsized and sank 14 miles off the Lizard peninsula in Cornwall on January 15, 2004. Many suspected a nearby submarine pulled it under.

A French prosecutor said that there was no evidence to support the claim that a submarine was involved, nor that it was a fishing accident.

Britain's Royal Navy has previously denied claims that one of its nuclear submarines caused the sinking. A French TV documentary had suggested the Plymouth-based submarine HMS Turbulent collided with the vessel before it went down.