HMS Defender was sailing from Odessa in southern Ukraine to Georgia. To get there, it passed south of the Crimea peninsula, which Russia annexed from Ukraine in 2014 in a move that has not been recognised internationally.
While Moscow claims the peninsula and its waters are Russian territory, the UK says HMS Defender was passing through Ukrainian waters in a commonly used and internationally recognised transit route.
BBC defence correspondent Jonathan Beale was on the deck of HMS Defender in the Black Sea as it was harassed by Russia’s military.
source: bbc.com