The 65m submarine was sunk by British Submarine HMS C-24 and decoy trawler Taranaki on June 23, 1915, as part of what the enemy later described as a 'dirty trick' but for home forces represented the first success of a covert naval operation, now famously referred to as "Q-ships".

For years the final resting place of WW1 U-40 was thought to be much closer inshore near Girdle Ness than her actual position proved to be.

There have been a number of unsuccessful expeditions over the past decade or so which makes Marine Quest's discovery even more of an achievement.