What happened off Crimea before 26 June 2021?

What had the Black Sea become by 26 June 2021? In the days before that date, it had turned into the setting for an open exchange of warnings between Moscow and London.

The dispute centred on the Royal Navy destroyer HMS Defender. On 23 June 2021, Russia's Defence Ministry said a Russian Navy patrol ship had fired shots and a Su-24 attack aircraft had dropped bombs in the ship's path after it reportedly entered Russian-claimed territorial waters near Crimea. The UK Ministry of Defence rejected that account. It said the Russian activity was part of a military exercise in the vicinity and denied that any shots or bombs had been directed at the British vessel.

On 24 June 2021 the argument escalated. Russia had already summoned the British ambassador over the incident. It then warned that it would bomb British vessels if the Royal Navy took any further provocative action in the Black Sea.

London held its position. The UK said the vessel had been in Ukrainian waters and that it was entirely right to use the route. It added that the Royal Navy would always uphold international law and would not accept unlawful interference with innocent passage.

By 26 June 2021, then, the two governments had set out sharply opposed versions of where the ship had been and what had happened around it.