Summary Powerful mercenary's forces won battle for Bakhmut He has heaped insults on Russian armed forces' top brass Criticism of war and authorities taboo in Putin's Russia But tacit approval within his inner circle, say sources MOSCOW, May 23 (Reuters) - Yevgeny Prigozhin on Saturday delivered Vladimir Putin one of the few battlefield victories of the president's 15-month war in Ukraine. Even then, Russia's most powerful mercenary could not resist breaking the taboos of Putin's tightly controlled political system. Holding a Russian flag and with an automatic weapon slung over his shoulder, Prigozhin announced the fall of the Ukrainian city...