THE LAST time that Russia fired on a British warship was in 1917, when a Bolshevik submarine torpedoed a destroyer in the Gulf of Finland. The last time it happened in the Black Sea was during the Crimean war over 165 years ago. So it was a surprise when Russia declared that it had not only fired warning shots at HMS Defender, a British destroyer passing through Crimean waters on June 23rd, but had also dropped bombs in its path.

The precise sequence of events is contested. Russia says that the British warship crossed 3km (two miles) into its territorial waters off Crimea, near Cape Fiolent (see map). When the Soviet Union broke up, Crimea became part of Ukraine. Russia occupied and annexed it in 2014. It thus claims the patch of sea in question, even though most countries, including Britain, regard the annexation as illegal. Russia said it “halted the violation” with warning fire and, 11 minutes later, with 250kg bombs dropped from Su-24 bombers.

Jonathan Beale, a reporter from the BBC aboard HMS Defender, says that the ship did indeed transit Crimean waters, and did so deliberately, presumably to show that it still considers the area in question part of Ukraine. Britain’s defence ministry said that the Defender carried out a “routine transit” from Odessa to Georgia through Ukrainian waters. There were no shots fired at the ship, it says, nor bombs dropped in its path—merely a previously-announced Russian gunnery exercise nearby. Mr Beale says that shots were audible, though presumed to be “out of range” of the ship, and that more than 20 Russian planes flew overhead.

Russian state television played up the incident. It portrayed it as part of an American plot to encircle and undermine Russia. (The Kremlin initially cited NATO’s aggression as justification for the annexation and subsequent fortification of Crimea.) Had HMS Defender not fled, the commentators crowed, all that would have been left of her would have been the lifebuoys.

Whatever happened, it was out of the ordinary. Western countries routinely decry Russia’s occupation and annexation of Crimea—most recently at a NATO summit on June 14th. On June 23rd the European Union extended economic sanctions on Russia stemming from the annexation for an eighth successive year. But neither America nor any other member of NATO is thought to have gone as far as sailing a warship with a journalist aboard through Crimea’s waters to flout Russia’s claims (though Russia accused HMS Dragon, another British destroyer, of doing so last October; there were fewer public fireworks on that occasion). “As far as I know,” says Dmitry Gorenburg, an expert on the Black Sea at CNA, a think-tank in Washington, “this is the first time a NATO warship has entered Crimean waters since 2014.”

Britain’s move was bold, but risky. Russia has built up a large military presence in Crimea, including advanced missile, air-defence and jamming systems. HMS Defender was a considerable distance from HMS Queen Elizabeth, the aircraft-carrier that she escorts, currently on the other side of the Bosphorus in the Mediterranean. It helps that an American intelligence-gathering plane was watching from above. But Britain’s willingness to run the risk reflects, in part, its torrid relationship with Russia, which has not recovered from Russia’s attempted assassination of Sergei Skripal, a former Russian intelligence officer, in England three years ago.

It also points to a wider shift in Britain’s defence posture. In a series of documents published over the past year Britain has set out a new strategy involving the more active use of military forces around the world. They called for “continuous operating on our terms and in places of our choosing”, including actions “that may test the traditional limits of statecraft”.

Britain’s support for Ukraine, which has also lost territory in its east to Russian-backed separatist militias and continues to skirmish with them, is a good example of this. Britain’s armed forces are already training Ukrainian troops and providing military assistance. In September, 250 British paratroopers conducted one of their largest air drops in decades in the country. Then on June 22nd, just a day before HMS Defender’s Crimean foray, British and Ukrainian government ministers met on the ship’s deck and agreed to jointly build patrol boats and naval bases for Ukraine. Britain may also transfer two old minesweeping ships to Ukraine’s navy.

But Anglo-Russian antagonism is not the only source of tension in the Black Sea. In the spring Russia massed troops close to eastern Ukraine and in Crimea itself, provoking fears of an invasion. Though the build- up was halted in late April, some troops have stayed behind. Now Ukraine is preparing to host “Sea Breeze”, an annual NATO-led naval exercise which will run from June 28th to July 10th, involving 32 navies, including America’s. Russia has complained that the exercise will “increase risks of unintended incidents” and “inspire militaristic ambitions in Kiev”.

After a summit between Joe Biden, America’s president, and Vladimir Putin, his counterpart, in Geneva on June 16th, Mr Biden said that he sought “stable and predictable” relations with Russia. But he also drew some red lines, vowing a robust response if Russia conducted more cyber-attacks on America or stoked tensions in Ukraine. Britain seems to have focused on the second half of the message. Other European countries seem to be concentrating on smoothing relations. On June 23rd, even as the Defender sailed past Crimea, France and Germany called for the EU to invite Mr Putin to a summit of the bloc’s leaders.