Some excellent thoughts BSl, must have taken a long time to post. I think the truism that "Generals always fight the last war" very interesting, but what is odd is that I would argue the British army at the end of the 1st War was far more able in combined arms and use of armour and air power together than its 39/40 compatriot. Why did the British army unlearn all the lessons of the ww1?

JF, I'm not sure they did unlearn the lessons of WW1. But, in any case, it was the cost of WW1, in people and resources. WW1 was very unusual in 500 years of British/English history, all the way back to the Elizabethan era. Essentially, it is one of two instances, along with the Napoleonic Wars, when Britain committed it's total resources to a land war in Europe. Britain's traditional policy was to avoid war in Europe, devote most resources to the Navy, and try to act as a balancing power to the rest of Europe, without use of it's army if possible. Given the traditional reluctance to commit to major war on the Continent in context of the titanic costs of WW1 (to everyone involved, not just the UK), it was unrealistic to expect a huge British Army ready to try to drive to Berlin in 1939.

thank you for some very good posts

In a sense, a lot of the lessons learned were, if not forgotten, then put aside. Remember that the British Army before WW1 was very small and had to be expanded to an enormous degree. Two battalion regiments suddenly had 50 or 60 battalions, which needed officering. The best talent rose to the surface and were often young and open to new ideas. Montgomery was one of these and he certainly was a keen advocate of all arms warfare. Unfortunately, after the war, the army reverted back to its pre-war size and most of the young talented officers had to leave. It was mainly the conservative that were left in the army. Liddell-Hart was a voice crying in the wilderness; no one in the hierarchy wanted to upset the status quo.

I dont like what ifs. I dont see the point.

There's been a lot written and said about how the Allies were unprepared to fight the (ground portion of) WW2. It's true to a degree, but somewhat overstated. In fact, the British more or less invented modern mobile (armored) warfare. They invented the tank, then, in the 20s and 30s, Liddle Hart and Fuller more or less worked out the theory of how to use really mobile armor to best effect. And, the British DID experiment with armored formations and how to use them. So did the French - heaven help us all. As for America, there were some relatively famous war games and manuevers conducted in the 1930s when attempts were made to work out how to use mobile forces. There was enough foresight that one of the earliest tries involved a rag-tag group of civilian vehicles, standing in for the machines yet to be developed and built. IIRC, Patton was a participant in these manuevers and gained some useful lessons in the effort. The legitimate criticism is that the high commands of the era were not prepared to commit, totally, to a new style of fighting. In part, this was a lack of foresight and general inertia. However, to a degree, it was something imposed by politicians who were totally uninterested in creating large armies devoted to the offense, and to extremely tight budgets which wouldn't stretch to buying totally new and expensive machines in huge numbers. The Germans were better able to adapt to the new conditions technology had created, but that's because most of the resistance to change had been wiped away with the defeat of WW1. One thing a really devastating lost war tends to do is open the institutional minds of a military to change. The factors which tend to resist change tend to be discredited in the defeat, leaving a clearer field for innovation. Leaders tend to feel, "it didn't work THAT way, so let's try something else".

I think the biggest what ifs are If Goering hadn't started retalitory bombing raids on london and continued to pummel the RAF. Operation Sealion would have been succesful. Meaning the Germans probably could have taken Russia. Pearl Harbour would probably still happen but there would only be a pacific war for thr americans which they would win.

Well personally I doubt that SeaLion would have been a success. The Germans had nor roper landing craft and were relying on commandeered Rhine barges mostly to carry the troops. This meant that any assault was reliant on perfect conditions and total control of the sea. The latter never happened. The next point is, where would they have landed? The Pas de Calais/Dover crossing was the intended route and there are very few beaches on that section of the British coastline and all were heavily mined and defended. The alternative was to try to take a port. All the ports on that section of coast were heavily defended. As the Canadians found at Dieppe, assaulting a defended port is a recipe for disaster.

I think the obvious thing that would have altered the war is simply the German invasion of Russia. Had Hitler not invaded, the outcome would have been inevitably altered.

I concur with Heorot. After Norway, the German Fleet was in no condition to protect an invasion. The Royal Navy was to all intends and purposes intact. They might have suffered terrible losses, but would have destroyed the invasion fleet. The land defences in june and july 1940, just after Dunkerque were a pushover; but much was made good, so in september/october 1940 an invasion was far from a sure thing. The RAF could not be destroyed: There were still bomber-pilots that could have been retrained rapidly - the only airstation out of commision for any length of time was Manston. Had Fighter command moved north of London, the German Bombers would not have had fighter protection, and warning time from Royal Observer Corps was sufficient, this would have lead to slaughter experienced during the one attack from Denmark/Norway.