Dr Gary Sheffield on BBC History site rubbishes Donkey myth.
His conclusion,
He (Haig) encouraged the development of advanced weaponry such as tanks, machine guns and aircraft. He, like Rawlinson and a host of other commanders at all levels in the BEF, learned from experience. The result was that by 1918 the British army was second to none in its modernity and military ability. It was led by men who, if not military geniuses, were at least thoroughly competent commanders. The victory in 1918 was the payoff. The 'lions led by donkeys' tag should be dismissed for what it is - a misleading caricature.