TV reporter Clive Gunnell is at the Royal Navy's Dive School in Her Majesty's Naval Base Devonport in Plymouth. Known as clearance divers for work in clearing underwater mines and munitions, navy divers undergo rigorous training. They no longer use standard diving dress of a canvas diving suit, a copper or brass helmet and heavy shoes with a linesman above water who would be responsible for the lifeline or oxygen pipe. Rebreather systems made the apparatus self-contained.