"Passchendaele was not a campaign designed by the British command in terms of what had been learned by this stage of the war.
"Some things the British army could now do. Six weeks before this campaign started, it captures Messines ridge as a preliminary operation. To do it, Haig's forces made careful calculations about weapons and weather and objectives.
"This did not happen during the Passchendaele Campaign. Haig's objectives, as I have said already, were ridiculously wide-ranging: the sweep all the way to the Belgian coast. And operations were not geared to take account, even, of factors such as the weather.
"Weather is a fundamental factor.
"Artillery can do things in fine weather that it cannot do in bad weather. If you are to succeed in landing your shells – you must have observation from the air. In this war, the air force is absolutely vital for just one thing: as an adjunct to the artillery. It sees where the enemy positions are, it photographs them, it reports where your shells are landing, it tells you to correct the range. You've got to have your flyers up there, observing.
"Correspondingly, you must have fighter planes up there protecting your observers, because, otherwise, enemy fighters will come and shoot them down. So you must have your planes in the air.
"The great Passchendaele Campaign is a three-month campaign; and two months of it are fought in pouring rain.
"The airplanes can't go up, so your artillery can't hit the enemy guns. Your shells land in the mud, so they don't explode effectively. Your troops that are supposed to be moving forward, behind the creeping barrage, are caught in the mud, and so, can't keep up with it. The whole thing is simply inappropriate to the lessons that have been learned – quite apart from the fact, as I have said, that the objectives were those far-off positions that no attack in WWI was ever going to be able to achieve."