A Portuguese submarine taking part in a Nato exercise off the coast of Cornwall became snagged on the nets of a French trawler.

The warship Tridente was caught about 35 nautical miles south west of Plymouth at about 6am on Monday.

It was below the surface when it became snagged on the nets of Daytona, a French fishing boat.

Damage was caused to the nets of Daytona, which was in the area fishing at the time.

A Royal Navy spokesman confirmed there were no casualties from the incident.

The spokesman added that an investigation into the incident would now take place.