LONDON - When, in February last year, Russian tanks first rolled over the borders of Ukraine, two assumptions were shared by all the actors in this drama: that the war would be short and that it would conclude with a Russian victory.

A year on from that fateful move, both Russia and the West are locked in a long-term attrition war which has already cost the lives of around a quarter of a million people, one from which neither side is likely to emerge with a resounding triumph.