The first British diver to see the Titanic wreck has paid tribute to his friend, the pilot of the stricken sub, saying he is an "extraordinary explorer" who knows the wreck "more than anyone else".
It comes as the search for the RMS Titanic Expedition Mission 5 submarine continues after last being seen on Sunday carrying passengers to the famous wreck.
The US Coast Guard is currently searching an area "about the size of Connecticut" for the missing submarine, which has five people inside.
