The Soviet navy had practically no ability to contest the Mediterranean and Germans, Poles, and Hungarians wouldn't exactly be eager to fight the Western Allies at Stalin's behest. Additionally, the Soviet military forces in Europe were decidedly inferior to those of the Allies and their economy was in a shambolic state. All in all a recipe for disaster.
Navy in the med? Of course not. But simply clogging the RN and USN outside of the Black Sea by lining up the 30 or 40 subs the Soviets had in the Black Sea against the Bosphorus means any break in movement by enemy naval forces would be suicidal; or very very very heavy to the point shore reinforcements would be able to deal the final damage.
Also.......what?
This is from
Operation Unthinkable: The Third World War: British Plans to invade the Soviet Union by Jonathan Walker
Chapter: US War Hawks
" The US Joint chiefs began conducting espionage and intelligence reporting during the ending months of WW2 in Europe with the goal of a confrontation with the Soviet Union. It assessed Soviet Military Capability on the European Continent with growing fears of paranoia regarding the Soviets and their infamous Red Army. They concluded that out of the 264 Soviet Divisions in Europe, the Soviets would be able to utilize around 81 of these Divisions in offensive operations alongside 25,000 tanks, and 60,000 artillery pieces. Due to this factual black lining, the joint chiefs concluded that should war break out the Soviets would be able to overrun western Europe. However the truth is slightly more complex than that. In reality that Soviets were capable of utilizing 92 Divisions offensively with 28,000 tanks and 64,000 artillery pieces. However despite this increase in numbers, the Soviet logistics would not allow the Red Army to enter France. At most, it would allow Germany to be overrun completely alongside some places of Netherlands. Such an alarming prospect made the US Army Joint Intelligence Committee to calculate the effect of 'blocking' such an offensive into Europe by unleashing nuclear weapons. 20 Soviet Cities were chosen by the US Intelligence Committee to become radioactive wastelands, however the American Joint Intelligence Committee was excluded from American nuclear secrets, and later from declassified information after the fall of the Soviet Union, it was found that such an attack would have been suicidal as simply 5 of these bombs landing would be an immense success as the Red Airforce and their ground defense network would have made an indepth aerial attack to plant those bombs nigh impossible."
"Allied Intelligence and maps regarding the Soviet Union were also very faulty and outdated, with most maps coming from the 1925-37 era and by 1945, much of the mapping of the Soviet Union had become obsolete. Many cities had been abandoned, and many new ones like that off the Soviet Secret Cities propped up. Many American and British Bombs would have been hitting debris simply for the sake of it and with no real end gain except for perhaps the danger of being gunned down."
Chapter: Home Front
"Whilst many British and American leaders had blustered about War with the Soviet Union, such an event would not have sat well with the population at home nor the army. In such an event, Britain and America would have no support from France, and De Gaulle emphasized on this. Around a third of the French Army was communist or socialist in leaning, and around the same proportion of ministers in the French cabinet were communist. Almost all of the recovering French economy and industries were centered around Trade Unionists and Socialists. Such a war with their Communist 'Motherland' would have shut down the French economy and would have pushed the shaky liberated France to the brink of civil war, which was something every Frenchman wanted to avoid. The same was the case in Italy where the Communist militias were armed to the teeth and had been exponential in the death of Fascist Italy. The Operation would have seen a massive upsurge of communist guerillas and rebellions in Italy, France and the Benelux, and not in small numbers either.
However the case of industrial shortage and problems does not end in France. In Britain and America itself, many Left-wing unions controlled a good deal of wartime industries; moreso in Britain than in America, however they made their presence known in America as well. A War with the Soviet Union would be running the risk of cutting off 8 to 10% of British industrial potential and around 3 to 4% of American industrial potential. In absolute terms to us these percentile does not seem like much, however for a war effort, even a difference of 2% could be war winning.
The public opinion would have also been very unfavorable. In 1939 it was Germany who struck first, and in 1941 it was again Germany. In this scenario it would the Western Allies striking first at the perceived enemy that Allied propaganda had made out to be 'friend of the allies' for the past 5 years. So much so that many in the west believed that fighting 'Uncle Joe' was out of the question. There was also a running risk that many American and British units would mutiny against a long and hard slog against the Soviets, like the Wanna Go Home Mutinies and Royal Navy Mutinies of late 1945 and early 1946 when tensions with the Soviets started to run high. The prospect and eventuality of war would have certainly led to many desertions and mutinies, something that was not sustainable for the Western Allies.
It was also highly likely that huge amounts of infrastructure in Europe and Britain would have been shut down by trade unionists and especially in Germany where the communist sympathizers had been suppressed by the Nazis. In fact it was likely that many communist militias would have opened up mini fronts in Germany as well which would wreck utter havoc on possible Allied lines.
On the long run, the operation was increasingly unfeasible. Ever since mid-1944 Britain had been dissolving a division a month, and by the end of the war still had chronic manpower problems, the British Army would not have been able to advance properly into Soviet Occupied territory and would have largely been able to only act as reserve troops for the American army which was the only allied army in Europe which could have gone on the offensive against the Soviets.
However what made the plan inevitably unfeasible and very unlikely was that the Soviets knew about the plan. It is not known when or how, and it was probably the Cambridge 5, however from between December 1944 to May 1945, the Soviets and Joseph Stalin got ahold of information that the British and Americans by allegiance were planning
some kind of attack on the USSR. They did not know the clearer details or finer objectives, but they knew enough to become extremely paranoid, and was one of the factors why the Red Army regrouped in Poland and the Elbe River. Such a preparation for war would have made the Soviets know immediately and the Soviets would have started defensive operations and constructions immediately. Knowing that there was a high chance the Soviets already knew, the plan was scrapped by both the US and UK."
Chapter: Quick Victory?
"Economically and Militarily putting the facts before us, it is much more easy for us to analyse the likely outcome if the operation went ahead. It is highly possible that such a war would have led to a negotiated agreement, however it was also highly likely that the war could have gone sideways. In the long term, the Western Allies could have pushed the Soviets towards the Elbe, however in such a case, the Western Allies would have to be willing to give up Iran, Greece and Iraq to the Soviets, as the disparity between Soviet and Allied forces in these areas were in an even higher disparity than in Europe.
It is also almost inevitable that the 1.2 million men Stalin had placed in the Far East eyeing Japan would have been immediately transferred to Central Asia and Iran from where they would strike. This would be extremely problematic as the Indian Situation for the British was getting worse, and the third highest political association in the British Raj was communism, which made the likelihood of internal problems hindering any possible indian commitment even higher. The Allies had in their zeal to supply the Soviets with Lend Lease built the infrastructure of Iran to the levels that the Red Army could take advantage of them and invade Iran and Iraq. The loss of these two nations and their natural resources would have been a heavy blow to the Western Allies and bring communism to the borders of India. This scenario was almost inevitable and both American and British observers agreed on this fact. Greece would have most certainly fallen. Turkey in such a scenario would have likely opted out and play both sides off one another; though being surrounded by communists on three sides would have made Inonu more amenable to some concessions to Kremlin.
In conclusion, with all economics, and home fronts and all facts taken into account, the Western Allies could have won Operation Unthinkable......at the risk of making the Middle East a Soviet Lake, and making Western Europe a communist guerilla paradise. Such an event would have taken up millions of Allied Lives, coupled with millions of Soviet Lives, and there was still a good amount of chance that the Soviets would have been able to drive to the English Channel; if France got involved at all; which would have had disastrous consequences. The Soviets had stockpiled a humoungous amount of weapons and rations and their war economy could have functioned normally for another year or two. Such a scenario was why it was called Unthinkable, the benefits were too low, and the costs too high; and that is not taking into account the utter confusion that would reign in the Pacific Front as the Americans would have contend with the Red Fleet as well; which whilst small was no easy foe either and would guarantee another thousands of americans to the depths of sea. And the domestic situation in the western countries were not favorable for a war at all. Any excuse such as friendly fire would have been ignored as Soviets and British/Americans had been exchanging friendly fire ever since early 1945, in events such as when the Soviets managed to gain three B-29s out of a friendly fire incident. The operation had in the end been named aptly, for it really was unwinnable one way or another; as it would be trading one thing for another with very blurred goals while running the risk of making communists throughout Western Europe rise up during the time of their peak popularity."
So yes, the Soviets could have been pushed to the Elbe, put the end result would not be in favor of the Western Allies, and frankly if the war began, every side would be bending over themselves to stop immediately as the Labour Party in Britain would be raving mad and the Senate in America would be crying for impeachment the second war happens. France, Benelux and Denmark would opt out immediately alongside Italy due to their internal problems.