When will the guns fall silent in Ukraine? According to several Western intelligence sources, by May 9, when Russians traditionally mount a large military parade in Moscow; President Vladimir Putin may want to proclaim a "victory" in Ukraine by then and even arrange for the units that fought in Ukraine to march past him in the Russian capital's Red Square.

But some Western governments and analysts are not sure since there is also plenty of other evidence indicating that the war may go on for months and even years. For while Mr Putin's military has failed in its original plans to subdue Ukraine quickly, Russia can afford to keep a war of attrition against Ukraine for an almost limitless period.