Hi ck1: good question.
Not sure if you are referring specifically to the passing of a (the) Russian aircraft carrier through the English Channel en route to the E Med. That of itself is/was no threat at all - that's the required route after all - and probably won't be a great deal of use when it reaches its destination either, other than as a 'we are here' gesture.
So yes 'posturing'
Russia economically is a comparatively poor country despite its huge potential in natural resources. It has a GDP the size of Hungary, and roughly 25 times smaller than 'The West' combined.
It is however ruled by a criminal kleptocracy, and President Putin does not have to contend with a sceptical parliament or congress to get his way: rather 500-odd nodding dogs in the state Duma. Added to a complicit media especially TV
That does not mean Russia is not a threat though: it is a very real threat, and that is not just because of the stockpile of tactical nuclear warheads : Putin's biggest weapon is us really: will we really fight back if and when he invades the Baltic States? Who wants a nuclear war after all? And who would pass up all that lovely Russian money in London etc ?
It seems pretty clear that he wants to divide Europe, discredit the US and revert to a world where Russia can be a powerful empire in a world of large spheres of influence. That sort of world ended in a conflagration in 1914, and there's every chance, somewhere down the line, that it would do so again. So yes: Russia may not be about to invade Blighty or bomb us from an aircraft carrier, but long term, as long as we allow ourselves to be intimated by a weak illy, well sleepwalk into a bad situation.
Recognising that Russia is not powerful militarily should be the spur for us to act in our own defence, before it's too late.