Sure the initial efforts to use the Persian route were seriously hampered by the local infrastructure; but the point here is that the Soviets had insisted on being supplied as quickly as possible through the Murmansk-Archangelsk route. Thus, limited resources were allocated anywhere else. Once the PQ-17 disaster had taken place, both the Westerners and the Soviets had to admit that alternatives had to be developed. Resources were allocated and the port facilities, rail lines and trucking roads came into being in Iran. It's a matter of taking the right - and the obvious - decision.
It was the Americans who spent the resources IOTL, including construction personnel:
https://history.army.mil/books/70-7_09.htm
The British retained strategic responsibility for the area and direction of the effort to forward supplies to the USSR; the American mission's task was still only that of aiding them to effect these deliveries. If the primacy of the task of forwarding supplies to the USSR was recognized on the American side, the British were still in no position to place it above their own military needs. [10]
....
From Bandar Shahpur the railway ran north via Ahwaz and Andimeshk to Tehran and thence through the Soviet Zone to Bandar Shah on the Caspian Sea, through some of the most difficult mountainous terrain in the world. The railway was without adequate high-powered locomotives and rolling stock, the line was laid with light rail, and it lacked an automatic signal system to speed traffic. The British had placed the railway under military control and assigned a force of 4,000 soldiers to run it, but the locomotives and rolling stock promised from the United States were slow in arriving, and the increase in rail capacity came equally slowly.
To supplement the railroad, the British had four trucking routes under development, all operated by a quasi-governmental corporation, the United Kingdom Commercial Corporation, using native drivers. Two routes ran wholly within Iran, from Bushire and Andimeshk, respectively, to Tabriz within the Soviet Zone. A third started at Khanaqin on the Iraqi railway, ran north from Basra through Baghdad, and also terminated at Tabriz. The fourth involved a devious route running by rail out of Karachi, India, to Zahidan in southeastern Iran and thence by truck to Meshed in the Soviet Zone in the northwest. This last route was used but infrequently and the Russians objected that deliveries over it provided supplies too far from the fighting fronts. All the routes were over the poorest sort of dirt roads, and United Kingdom Commercial Corporation operations were seriously handicapped by lack of trucks and efficient drivers. [11]
Once it had been concentrated in Iran, the American mission was assigned some of the most essential tasks-construction of additional docks at Khorramshahr, operation of truck assembly plants at Andimeshk and Khorramshahr and of an aircraft assembly plant at Abadan, construction of highways connecting Khorramshahr, Ahwaz, Andimeshk, Tanuma, and Tehran, and assistance to the British in the performance of a variety of other tasks. The British Army and the United Kingdom Commercial Corporation remained in control of all transport operations. [12]
.....
The British remained unable to spare men or resources, and the Americans were reluctant to commit significant additional resources to the Middle East.
As a result, in no particular did progress during the three months after the May decision justify optimism. The heavy shipments to the Gulf ports inevitably brought an increasing threat of port congestion. Development of the ports lagged behind Shingler's predictions, and inland clearance, ever the biggest bottleneck, lagged even further. The Iranian State Railway, necessarily the primary reliance, was carrying, as late as August 1942, only 35,770 long tons of supplies for all purposes and of these only 12,440 were supplies for the USSR. The trucking operations of the United Kingdom Commercial Corporation, never characterized by a high degree of efficiency, were but a poor supplement. While the need for capacity for Soviet aid rose, The British found it necessary to add the burden of supply for the Polish Army they were evacuating through Iran to that of the British military and the Iranian civilian economy. While the two U.S. truck assembly plants at Andimeshk and Bandar Shahpur and the plane assembly plant at Abadan began operations in April, their capacity continued low and it was further limited by the lack of adequate port and inland clearance facilities. Such was the situation in the Persian Corridor when the Allies found themselves facing a new and more serious crisis in their effort to maintain even a limited schedule of convoys over the northern route. [14]
The Brits weren't in a position to improve on much themselves, as they were fixated on their own issues, leaving Iran with the leftover resources they had. The US infrastructure command actually committed the resources to building everything up, though the British command was technically in charge of running it, because of their existing command in the region to supply themselves and run the oil industry.
Let's examine this. AS I said, Germany had already lost by the end of 1942 on the Eastern Front. They had also lost in Africa. The 8th Air Force did not conduct it's first operation until 17th August 1942 when they sent a measly 12 bombers on a raid. Their influence in the war was great. Their influence in 1942? Minimal. The Germans were always going to go after oil in the South in 1942, US entry or no.
You've asserted that yes, but then ignored US contributions to the end of the year as well as the impact of US entry in late 1941 and on, as well as the guaranteed victory for the Allies that US entry meant, but haven't apparently considered how much different 1942 would have been without US entry or hope of entry. The loss in North Africa was a function of not only US material aid, but the influence of the USN and merchant marine aiding Britain, not to mention Operation Torch, which was only possible with US military resources. Without Torch North Africa is going to continue.
The first strategic bombing run by the USAAF in Europe was against Ploesti in June 1942:
https://codenames.info/operation/halpro-i/
That alone diverted 5% of the entire German air defense resources to the area starting in 1942, which was an enormous investment of resources denied to other vital areas.
https://www.abmc.gov/news-events/ne...merican-bombing-raid-over-europe-world-war-ii
After the Ploesti raid HALPRO Liberators and their crews became the first American heavy bombers dedicated to the Mediterranean Theater. Joined by B-17 Flying Fortresses from India, they became the 1st Provisional Bombardment Group (PBG), and the 376th Heavy Bombardment Group. They went on to attack the German Afrika Corps in North Africa, and the Italian Navy at sea. Completing 450 missions after the first Ploesti raid, HALPRO, the 1st PBG, and the 376th sustained the loss of 1479 officers and men.
[iv] Halverson earned the Silver Star for leading the Ploesti raid.
[v]
That was huge in the context of North Africa at the time considering they were using heavy American bombers to attack Axis logistics.
And your reference to the first 8th Air Force mission is just for the first mission, they started stepping it up rapidly after that and were committing escort fighters for daylight missions as well. They were dozens of missions with several dozen heavy bombers attacking targets all over Western Europe in 1942, which forced the Luftwaffe to respond with more fighters and FLAK deployed to the region and away from other areas.
As to the plan for the eastern front in 1942, oil was a long term goal, but the rush to get them as recklessly as they did, violating the pre-campaign plan to take Stalingrad first before invading the Caucasus was a function of US entry and the need to get the oil ASAP, which put them in the vulnerable position of trying to do both at once.
In terms of North Africa, TORCH could easily have been conducted by the Royal Navy. In terms of troops for such an operation, with no Japan 6 ANZAC Divisions and at least 4 Indian Divisions would have been available of the 20+ formed. Possibly more, since the UK does not suffer the loss of an infantry division of their own in Singapore, nor does Australia.
I'd look at how many USN ships participated and figure out where the extra RN ships are coming from. Then you have to figure where all the British ground forces are coming and then deal with the fact that the French would fight the British much more than the Americans; the French generals the Allies negotiated with even warned them to only send Americans in the first waves, because the French troops and Vichy loyalist generals would fight the Brits hard as they already had been:
https://en.wikipedia.org/wiki/Forei..._with_Britain_in_Dakar,_Syria,_and_Madagascar
There is the risk Vichy might even join the war against Britain if the fighting bogs down in Algeria, as that was considering part of Metropolitan France.
Also where is the shipping coming from to move 6-10 divisions from the Pacific to Europe, especially when the Brits needed to retain a strong presence in the Pacific to deter Japanese potential aggression?
Lend lease up to end 1942? Well, the British would likely have sent what they sent to the USSR in any case, so that can be discounted. In fact, they may send more. US shipments to the USSR? Around 2,400 tanks delivered, 2,100 aircraft and 79,000 soft skinned vehicles. The later were certainly significant, but it must be remembered that many of these arrived November/December 1942 and saw little usage prior to end 1942.
All they could send was what they sent IOTL, they had too limited resources to send more given shipping and escort constraints. If Japan isn't in the war they have the resources to prevent L-L into Vladivostok, which could deprive the Soviets of 50% of L-L alone. There isn't the 1942 build up of Iranian infrastructure without US entry into the war. There isn't US naval resources put into helping the British globally ship and escort things either. So at best they are able to send what they did IOTL, while OTL L-L is throttled due to lack of US active participation.
And by end 1942 the Germans were stuffed. Going into another winter with Stalingrad cut off and their advance halted. In their death thrones in Africa. No way to adequately defend Sicily, the fall of which would cause Italy to drop out, like OTL. With no Japan, the Royal Navy can deploy the whole Eastern Fleet in the Med, consisting of 7 battleships or battlecruisers, a carrier, 4 heavy cruisers, 8 light cruisers and large numbers of smaller vessels, many of the later of which can be injected into the Atlantic battle. They can land anywhere they want in Greece or the Balkans.
Only because of US entry and the impact that had on the long term. Even ignoring the huge benefits that would come to the Axis due to no US participation in 1942, without massively increase US participation in 1943 the post-Stalingrad boost the Soviets got by the Axis diverting resources to deal with the combined Anglo-US forces in the Mediterranean and in France and Norway plus 8th Air Force bombing of Germany proper it is unlikely they could have pulled of their OTL advances; not only that, but without USAAF daylight bombing the RAF is going to get it worse in 1943 at night, because the Luftwaffe could concentrate resources on fighting that specific type of strategic bombing rather than fighting two separate strategic bombing campaigns.
Tunisia per OTL isn't happening without US resources and if anything Monty stalls out again in Libya, while limited British forces either don't allow them to land a separate army in French North Africa or they get bogged down and are stuck fighting the French bitterly. Once the Brits go all in in North Africa they don't have the resources to threaten France, so the Germans can strip out a lot of their forces in Western Europe to fight in North Africa. That said this assumes that things go exactly as IOTL in 1942 in North Africa, which is hardly a guarantee without US help.
BTW tell remind me how the British landings in the Aegean worked IOTL without US help?
https://en.wikipedia.org/wiki/Dodecanese_campaign
Besides the Brits cannot strip out the Far East, because they need to stay strong to deter Japanese aggression. If they strip it all out then they open themselves up to attack and they know that, which is why in 1941 so many forces were locked down there anyway, not to mention they had to garrison the colonies to make sure they stayed loyal. India was after all in the throws of an independence effort and British efforts to curb it were only increasing the tensions:
http://www.open.ac.uk/researchprojects/makingbritain/content/1942-quit-india-movement
Yes, it will take longer, but eventually Germany falls. It's failure to beat the USSR quickly enough makes that a certainty. Aircraft, Tanks? Germany made the best gear, but just not enough of it to beat a monolithic entity like the USSR with British support. Similarly with manpower. British greatest weakness? Also manpower. However, with no Japan it is reasonable to assume the following can be used in the European Theater by late 1942 that were busy in the Pacific:
You keep asserting that, but seem to be ignoring the reality of the challenges that would go along with that without active US participation and the resulting butterflies.
The USSR's economy was smaller than Germany's alone by a wide margin by 1942 due to the huge losses inflicted on it in 1941 and the 1942 offensive. The L-L that the USSR got IOTL is going to be smaller ITTL at least because without US participation the Persian Corridor isn't getting built up, while the Japanese may well get more aggressive about preventing shipments to Vladivostok, which Russia couldn't do anything about due to being 'all in' in Europe. The Axis in Europe don't need to outbuild the Soviets+UK, they just need to out kill them, which they were doing until US entry tipped the balance.
And no it is not reasonable to assume the Brits would even have those extra forces, let alone be able to spare them for Europe. No Japan in the war means less Indian recruitment, as it is unlikely those Indian volunteers would join if they weren't defending India against invasion from Japan, while the ANZACs would want to retain forces to deter Japanese aggression. Plus there was the whole need to garrison the Empire, which is why extra forces weren't being transferred from the Pacific to Europe in 1941.
9th, 11th, 14th, 17th Indian Divisions
5th, 6th, 7th, 8th and 1st Armoured Australian Divisions
2nd, 3rd New Zealand Divisions
18th Infantry Division
All of the Indian divisions you list were available pre-1942 and yet they were retained in Asia to garrison Britain's colonial holdings, they weren't available for other duty. At best the 14th and 17th divisions would go to their intended place in 1942...garrisoning the Middle East. They weren't specifically intended for an active combat area against Axis forces.
The Aussie divisions were intended for home defense/training and were only activated for more BECAUSE of Japanese entry into the war:
https://en.wikipedia.org/wiki/5th_Division_(Australia)#Defence_of_Australia,_1939–1942
Without Japanese entry it stays as a training unit.
I'll grant you the 1st Aussie armored would go to North Africa.
The 6th Aussie was cooling it's heels in Syria as of the time of Japanese entry, not having done much since getting knocked around in Crete and North Africa. Same with the 7th minus Crete. The 8th was to join them in occupying the Middle East.
The 2nd NZ division was kept fighting in North Africa IOTL, so I don't know why you included them. The 3rd NZ division was only formed in response to Japanese entry. It's formation apparently caused a bunch of manpower problems for the NZ economy and wasn't even able to be brought up to full strength, so had to disband a brigade shortly after forming and in 1944 it had to be disbanded entirely:
https://en.wikipedia.org/wiki/3rd_Division_(New_Zealand)
And yes the 18th division was supposed to be in the Middle East. BTW it required American transport to get there and only 1 division could be transported instead of the 2 asked for by Churchill.
So let's revise the numbers based on what was actually available IOTL:
None of the Indian division were intended to be in combat, so they'd be there to free up the Aussies from their occupation of Syria-Lebanon.
Which means the 6-8th Aussie divisions and the 1st armored would be in North Africa as intended. The NZ division were either there or wouldn't be formed ITTL. The 18th UK division would be in the Middle East too.
So 3 Aussie infantry divisions and 1 armored + the 18th division. They were all intended for the Middle East and would be rotated into combat as needed. If anything that prevents Rommel's logistically disastrous Egyptian invasion in 1942, which means the campaign continues into 1943. Those extra divisions just end up supplementing the British 8th Army in North Africa rather than being available for invading French North Africa, especially considering their supply lines and where they are coming from. Which means Operation Herkules goes off and Malta is taken, which changes a tremendous amount about the North African campaign, as does of course Rommel not being able to invade Egypt due to extra British forces being in place in 1942.
BTW without the US in the war, the USS Wasp won't be there to ferry 48 Spitfires to Malta in April 1942:
"
Club Run" deliveries required the short-range fighters to be loaded onto an aircraft carrier in Britain or at
Gibraltar and taken to within flying range of Malta where they would be "flown off" and make their own way to Malta. There had been several earlier "Club Runs" but by this time, no suitable British carriers were available.
[note 1] The situation was urgent, so, after a personal request from the British Prime Minister,
Winston Churchill to the American President
Franklin D Roosevelt, the
American aircraft carrier
USS Wasp was loaned for a "Club Run".
Note 1:
"
Club Run" deliveries required the short-range fighters to be loaded onto an aircraft carrier in Britain or at
Gibraltar and taken to within flying range of Malta where they would be "flown off" and make their own way to Malta. There had been several earlier "Club Runs" but by this time, no suitable British carriers were available.
[note 1] The situation was urgent, so, after a personal request from the British Prime Minister,
Winston Churchill to the American President
Franklin D Roosevelt, the
American aircraft carrier
USS Wasp was loaned for a "Club Run".
Or their 2nd run in May:
USS
Wasp returned to
Glasgow on 29 April 1942, where she loaded 47 Spitfires Mk Vc at
King George V dock at
Shieldhall.
[1][note 1] The condition of the aircraft was no better than it had been for
Calendar; the essential long-range fuel tanks still fitted badly and, consequently, leaked.
Wasp's captain, Reeves, refused to continue loading until the fault had been fixed on some tanks and then agreed to perform the remaining work with his own personnel. This fault had been notified to the British authorities as it had affected
Calendar and its recurrence was a serious embarrassment.
[3]
Wasp and her escorting force (Force W) sailed from
Scapa Flow on 3 May. A further 17 Spitfires, delayed from previous "Club Runs", were transported by
HMS Eagle, which joined Force W on 7/8 May from Gibraltar.
[3][note 2] On 9 May 1942, 64 Spitfires were flown off USS
Wasp and HMS
Eagle (61 arrived). One aircraft and its pilot was lost on takeoff.
On Malta, lessons had been learnt from the disaster of Operation
Calendar and detailed preparations had been made to get the Spitfires airborne before they could become targets. On arrival, aircraft were dispersed into protected areas and rapidly refuelled and rearmed - one within six minutes of landing - and the newly arrived fighters were airborne, with fresh, experienced pilots, over Malta awaiting the air raid intended to destroy them.
[1] In the mêlée, the Italian formation (
CANT bombers escorted by
MC.202 fighters) was seen off
[1] and 47 German aircraft were destroyed or damaged, for the loss of three British.
[note 4] This air battle (sometimes dubbed the "Battle of Malta") abruptly ended daytime bombing of Malta.
[3]
No Wasp, no transfer of aircraft and learning from the mistakes of the April operation and of course no inflicting of damage so severe that daylight bombing of Malta was ended for a time.
So that leaves HMS Eagle to start it's Club Runs in June and in the meantime leaving the Axis air forces free to bomb the island for months before inflicting damage on the Eagle's aircraft in June when they arrive, as the OTL lessons from the losses suffered in April aren't learned ITTL. That's also assuming butterflies don't have the HMS Eagle get sunk earlier than IOTL as it faced a lot of attacks before it's August 1942 sinking by a Uboat; butterflies could well mean the OTL attacks it faced sink it, especially without help from Malta due to not having the OTL Wasp delivered aircraft to help.
Again major changes compared to OTL.