A needless provocation by the Royal Navy or the legitimate exercising of a right of passage at sea?
That depends on your viewpoint.
Britain, strongly supported by Ukraine, insists that HMS Defender was taking the shortest, most direct route across the Black Sea, from Odessa, in Ukraine, to Georgia.
But that route passes just a few miles from the shores of the Crimean peninsula which was annexed by Russia in 2014 in a move condemned by the West and never internationally recognised.
That is not how Moscow sees it.
Despite a raft of sanctions imposed at the time, it has portrayed its annexation of Crimea, with its significant population of ethnic Russians, as returning the peninsula to its rightful owner: Mother Russia.
The port of Sevastopol, close to Wednesday’s incident, is home to a major Russian naval base and its Black Sea fleet.