the trailer for the upcoming dad's army movie states that in 1944 Britain was on the brink of defeat. of course anyone who knows about ww2 can tell you that that is a load of hogwash and that if anything, it was the Germans who were on the brink.
so your challenge is to make the trailer true and create a situation where Britain appears to be on the brink of defeat in 1944.
The Allied cryptanalysts re-break Enigma a few weeks earlier in 1940. (At this time it was a joint British/French/exiled-Polish effort.) The break is in time to alert the Allies to the intended German invasion of Norway, which the Allies crush.
This spectacular success leads to much semi-private bragging among Allied spooks, in particuiar by Colonel Bertrand, a key figure in the French-Polish end of things, who is entitled to much credit but takes even more.
Some of Polish analysts are highly disgruntled. One of them unburdens himself to a representative of the the Daily
Zgoda, the Polish-language newspaper in Chicago. The
Zgoda prints a story revealing the wonderful success of the Polish analysts, which they fatuously think will not be read by anyone except Poles. But it is also read by a German-American butcher who grew up in Posen/Poznan (a largely Polish area of Imperial Germany that went to Poland in 1918), and reads the
Zgoda to check up on Polish-American competitors' ads.
So the ULTRA secret is blown at the start. The defeat in Norway, and the revelation that German signals security is non-existent, forces a delay in FALL GELB, all the way to late July.
The war appears to be going much better for the Allies; Germany seems to be contained. FDR decides that he isn't needed to steer the country through the war crisis, and doesn't run for a third term. As in OTL, he discloses this decision at the Democratic National Convention, but does not arrange for "the voice from the sewer" to start a "draft".
The convention is thrown up for grabs. Neither of the two overt candidates, VP "Cactus Jack" Garner and ex-Postmaster Jim Farley, has much real support. Several other figures declare interest or are touted by one faction or another. One of these has prepared for the opportunity: Senator Burton K. Wheeler of Montana, who has already formed a campaign committee. Wheeler is a passionate New Dealer - he jumps to an early lead, and then makes a deal with Farley to be his running mate (OTL he actually suggested this before the convention). Wheeler is nominated.
The Republicans have already nominated businessman Wendell Willkie. Wheeler is some ways a very problematic candidate, and he's not
Roosevelt. But also he's not breaking the third-term tradition, and Willkie is a first-time candidate who in the opinion of some OTL observers self-destructed.
So Wheeler is elected in November. And Wheeler is a
fanatic isolationist.
Meanwhile, the Germans regroup: revamp their cipher systems and revise their plans for FALL GELB. They attack on 27 July. Despite the delays, the French army is still sclerotic, hidebound, mis-equipped, and mis-organized; France collapses in a month, and becomes a quasi-neutral German satellite. But Mussolini was unnerved by the Norway defeat, and stays out of the war.
The battle of France is followed by the blitz of Britain; there is no plan by Germany to invade, as it is too late in the year, but there is an intense bombing campaign. Hitler attempts to persuade Franco to join the Axis, but fails. However, Soviet agents get a transcript of the meeting.
They also reveal that Hitler is already thinking about attacking the USSR. Stalin has a cunning plan to divert and deter this. He offers Hitler all the oil and grain he needs to meet Franco's demands (and Mussolini's). He also has Soviet intelligence feed the Abwehr a true order of battle for the Red Army - which is much larger than the Abwehr's estimates.
Hitler decides he has to break Britain before taking on the Soviets, and for this he needs Spain and Italy more than he needs French neutrality. In February 1941, Italy and Spain declare war on Britain. Axis forces occupy French North Africa, neutralize Gibraltar, and invade Egypt. German and Italian naval forces based in Spain raid all across the Atlantic, along with U-boats. Britain is semi-blockaded.
In return for the goodies, Hitler agrees to Stalin's renewed conquest of Finland, which is carried out in April and May 1941.
Meanwhile - President Wheeler disclaims any U.S. interest in upholding colonial rule in Southeast Asia. Japan decides this is a green light, and seizes the British, French, and Dutch colonies, and also occupies the South Pacific. Australia and New Zealand are helpless to resist Japanese raids, and are forced to withdraw from the war. (The weak RN force sent to oppose the Japanese is annihilated.) Many Americans express outrage over Japanese actions such as the bombing of Sydney and the seizure of Fiji, but Wheeler stands firm - the U.S. has no business interfering 7,000 miles away.
The Japanese fleet also scours the Indian Ocean, cutting off India and the Middle East. With Japanese assistance, Indian nationalists led by Subhas Bose seize control from British colonial authorities; Axis forces sweep the unsupplied British out of the Middle East.
All this is complete by August 1941. Britain nonetheless hangs on. The sea route to Canada is still open - barely, and the Allies hold French West Africa. There is no fear of invasion. But there is no Lend-Lease, and half the Empire has been lost.
But Hitler decides that Britain is reduced to impotence, and with the British blockade of Europe broken, Germany doesn't need Soviet gifts. Also, Stalin is tightening the spigot, and demanding payment - which Hitler can't afford.
So in August, the Axis invades the USSR. As in OTL, Stalin refuses to heed warnings, and the Axis attack is a great success. German planning was somewhat better informed than OTL; despite Hitler's manic optimism, the General Staff has allowed for greater Soviet reserves and the probability that the campaign will last through the winter. Also, the successful second Soviet campaign against Finland dispells part of the aura of incompetence created by the Winter War, so the Germans aren't as cocky going in. The 1941 campaign ends with the fall rains in late October; the Axis has taken Novgorod, Smolensk, Dnepropetrovsk, and the Crimea, and inflicted 4M losses.
When the Soviets counterattack in November, the Axis forces have been resting for a month after the offensive stopped. They take some hard knocks, but generally beat off the Soviets. Fighting pauses with the 1942 spring thaw.
Britain hangs grimly on. The Axis invasion of the USSR brought all the reluctant leftists over to the war side, but the endless bombing, the food rationing, and the tide of defeats has been demoralizing. Canada and South Africa are still supporting Britain, but both are balking at the seemingly limitless needs of the mother country.
In the rest of 1942: the Axis resumes the offensive. Axis forces take Leningrad and liberate Finland (at least that's how the Finns see it); British and Soviet force hold out in the Arctic from Norway to Murmansk. Axis forces drive on Moscow, but are stopped just short in a ferocious battle. Axis forces also sweep across Ukraine to the lower Volga and take over the isolated Caucasus from north and south.
Also in 1942: Spanish-German forces march on French West Africa, are repulsed. Italian-German forces retake Abyssinia and Somalia.
In 1943: Another round of Soviet winter counterattacks has limited success at heavy cost. The Axis summer offensive takes Moscow, but logistics and heavy casualties limit exploitation.
Food shortages, severe casualties, repeated defeats, and the strain of continual overtime war work demoralizes the Soviet people. Stalin's brutal repression of discontent causes further alienation. In October 1943, mutinies and local rebellions break out; rebels kill Stalin. A Vichy-style government surrenders in January 1944; Soviet Asia and the area east of Gorky remain unoccupied.
In Africa: Spanish-German forces remain stalled north of Senegal; their logistics make OTL Libya-Egypt look easy. But in east Africa, German-Italian forces take Kenya and Tanganyika. South African forces take heavy casualties. There is a quasi-revolution in South Africa by pro-Axis Afrikaners. South Africa leaves the war, and takes over Rhodesia, Bechuanaland, etc.
Since 1940: shipyards around Axis-occupied Europe have built several thousand Siebel ferries and similar shallow-draft motorized barges; an invasion of Britain is now physically possible. The Royal Navy has been severely ground down, while Axis shipyards have built many large "torpedo boats", destroyers, escorts, and light cruisers.The Axis battlefleet now includes 4 German, 7 Italian, and 3 salvaged French battleships.
With the end of the war in the East, Germany concentrates the whole Luftwaffe on the Channel in spring 1944, threatening to overwhelm the RAF. The ferries and barges are gathering in the Netherlands and Belgium.
It's 1944, and Britain is on the verge of defeat.