By Mark Trevelyan LONDON (Reuters) -President Vladimir Putin said on Thursday that Russia had barely got started in Ukraine and dared the West to try to defeat it on the battlefield. In an ultra-hawkish speech to parliamentary leaders more than four months into the war, Putin said the prospects for any negotiation would grow dimmer the longer the conflict dragged on. “Today we hear that they want to defeat us on the battlefield. What can you say, let them try,” he said. “We have heard many times that the West wants to fight us to the last Ukrainian. This is a tragedy for the Ukrainian people, …