“If you don’t enjoy the cold, it’s probably time for another pastime,” says Scapa Scuba dive shop instructor Kieran Hatton of the brisk waters surrounding the Scapa Flow wrecks off the Orkney Islands of Northern Scotland. Scapa Flow is the graveyard of the WW1 German Navy, which was scuttled in 1919.

His top pick for an intact vessel is the 155m-long S.M.S Coln, a German cruiser now on its starboard side in 36m of water.
Why go? “You’ll see the graceful lines of an early 20th century warship,” he says, “Plus a few guns are still in place – these things are as big as your arm