Opinions can differ about how successful an independent Ukraine has been in establishing democracy, curbing corruption or developing a modern economy. My view is that it has succeeded more than many of its critics allow. But in one respect, its achievement is stellar. In the crucial matter of getting its story out, Ukraine’s achievement may be second to none.

So it is, that pretty much the whole western world believes that what happened last weekend was a Russian lunge for exclusive control of the Sea of Azov – a vital outlet to the Black Sea that it shares with Ukraine. What it is now fashionable to call a “narrative” runs like this: plucky little Ukraine was just exercising its right to move two gunships and a tugboat from Odessa to its port of Mariupol on the Azov Sea, when big bad Russia obstructed their legitimate passage, rammed the tug, detained the ships, and captured 24 Ukrainian sailors – all with no justification whatsoever.

Russia releases footage of crew members from seized Ukrainian vessel

Now the Ukrainian president has appealed to the Nato alliance – via an interview with the popular German Bild newspaper – to send naval ships to the Sea of Azov “to assist Ukraine and provide security”. He had earlier imposed a month-long state of martial law on all Ukraine’s border regions, which has now been endorsed by the country’s parliament.

Thus the Kerch Straits, having seen the first direct clash between the militaries of Ukraine and Russia since the two parted ways in 1991, could now provide the backdrop for a confrontation that would be even more alarming: a direct clash between Nato and Russia, and – let’s not beat about the bush – a new Crimean War.

Before anyone rushes to potentially fateful action, however, it needs to be underlined that Ukraine’s narrative, persuasive though it might seem, is not unchallenged. Slow and clumsy, as so often in presenting its case, Russia has a different version, and this is that the Ukrainian ships flouted agreed regulations – by not giving notice of their arrival – and the clash was deliberately staged to bolster President Petro Poroshenko’s flagging support as he starts his campaign for re-election. Ukraine, it should also be said, denies this, and says its ships tried to give notice but could not raise any response. On the other hand, if you recall the saga of the non-murdered Russian journalist in Kiev, Ukraine has some rather bold form in the anti-Russia fake news department.

In fact, it is not impossible both versions are true, and the whole incident stemmed from miscommunication, only to be milked by each side for its own advantage. But – again, as so often – even a minor military clash tends not to stem from a one-off neglect of the small print, but from a bigger picture, and here context is all.

The Straits of Kerch, which divide the Azov Sea from the Black Sea, have been a source of tension ever since Ukraine and Russia separated, and there was almost a war in 2002-3. Then, though, both sides stepped back and agreed rules for joint navigation – rules that, miraculously, pretty much held until last weekend.

If the friction long predates Russia’s annexation of Crimea, however, and the two sides had continued to observe the joint navigation agreement until now, two after-effects of that annexation have certainly fed into the recent clash. One is Russia’s new bridge, which provides a road link from the Russian mainland to Crimea for the first time. The other is the increased Nato presence in the Black Sea region, under the guise of providing support to Ukraine.

The completion of the bridge in May makes it far easier than before for Russia to block the Kerch Straits – indeed, the use of a Russian freighter to block the narrow navigation channel during the latest incident suggested the bridge might have been designed with exactly that in mind. And this will only augment fears in Ukraine that Russia’s goal is to make the Sea of Azov an exclusively Russian body of water.

The other side of the argument is the growing western naval presence in the region – with Nato ships patrolling as close as they can legally get to Russia’s only warm water ports – and the de facto incorporation of Ukraine into the Nato defence system, if not formally into the alliance. In official parlance, Ukraine is a Nato “partner” – not protected by the famous Article 5, but integrated in almost every other way.

This arrangement reflects an uneasy compromise reached at the 2008 Nato summit, when most of the European allies opposed a US plan to admit Georgia and Ukraine. The official answer then was “no”, while keeping the “perspective” alive. Ten years on, largely out of sight of western electorates, Ukraine’s armed forces are being restructured, retrained and re-equipped, to be Nato forces in almost all but name.

There have been joint military exercises, including in western Ukraine in the autumn. The US is helping Ukraine build a new “maritime operations centre” at Ochakiv, to the east of Odessa – not far from Russia’s base at Sevastopol. Ukraine has also upgraded the port of Berdyansk on the Sea of Azov, officially to cater for bigger grain exports, but improved port facilities rarely serve only commercial purposes. There is also a significant Nato advisory presence in the upper echelons of the Ukrainian top brass and defence ministry.

Russia’s public silence about what it could reasonably regard as Nato’s expanding influence into its back yard might be surprising, unless you believe – as I do – that Moscow recognises it has essentially “lost” Ukraine – and Georgia. What Russia is unlikely to accept, however, is any direct threat to what it would see as its national security. And if existing arrangements for shared navigation in the Sea of Azov break down, Ukraine’s fears of losing this outlet to the Black Sea could prove well-founded.

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The risk is that, as with Georgia in 2008, Ukraine might overreach, in the expectation of combat support against Russia. Or that Russia might overreact to what has so far been a single clash in an already tense stretch of water.

Fortunately, it would seem caution is prevailing. Presidents Putin and Trump are keeping their distance. The EU failed to agree new sanctions and Nato has been noncommittal about Poroshenko’s request for new maritime patrols – and thank goodness: the last thing needed is for Nato to add its ships to the congestion around the Straits of Kerch.

But there is one area where outside engagement is sorely needed – and that is the revival of the stalled search for a settlement of the Russia-Ukraine tangle. As winter draws on, there is still fighting in Ukraine’s east, and last weekend’s confrontation at sea risks opening a new front.