An investigation has been launched into an incident in the Irish in which a nuclear-powered submarine almost collided with a ferry carrying over 1,300 passengers.
The near miss happened on November 6th and involved the Stena Superfast VII ferry that operates between the North of Ireland and Scotland but went unreported for some time.
The nuclear submarine is thought to belong to the Royal Navy and was operating at periscope depth at the time.
All Royal Navy Submarines are powered with a nuclear reactor and it is thought the sub may also have been carrying four Trident nuclear missiles.
A reported sighting of a nuclear submarine between Belfast and Stranraer on November 6th was confirmed and the Marine Accident Investigation Branch is still investigating.