Have a read about Operation Unthinkable.
Operation Unthinkable wasn’t called unthinkable because it was plausible, it was called unthinkable because it was an improbable “just in case” strategy
proposal in the event of the Soviet Union’s decision to spread it’s wings and push further west than permissible by the Yalta Agreement, even though affording Poland a “square deal” was mentioned.
Roosevelt and Churchill were not
unaware of what they had unleashed by underestimating Stalin & Co., so one might even say that Operation Unthinkable was a conscience balm for Churchill – one that might go down nicely in history books and show him not only in an better light in some distant future, but also as someone who thought ahead.
Operation Unthinkable was based on very far-fetched hypotheses of everyone wanting to, and more importantly being able to, pick up the bits and pieces and go back to war against an ex-ally/new enemy who, by that time, could swamp the remnants of British, other European, and American forces just by looking at them. The USSR by that time out-numbered this supposed New Group of Allies (which would inevitably include the remnants of the German Army thereby creating even more problems of ill-feeling and goodness knows what else) both as far as machinery was concerned and as far as man-power was concerned.
Operation Unthinkable was also counting on highly unlikely popular consent, and this means that of UK and USA citizens (the ones in Eastern Europe were already fighting their new Master hence the aforementioned Concentration Camps in this thread), and the even more unlikely ability (and desire of the population to "go without" for a few more years) to face the incredible costs of such a proposition. (Bear in mind that the UK paid off its World War II debt to the USA in December of 2006 – just a year ago!)
The proof of the pudding, however, lies in the iron curtain (the result of Yalta) being lifted only in 1989 – so Operation Unthinkable remains what it was most likely meant to be: a Political Conscience Soother, a spot of back-covering, and a way of amending negative opinion in history books – once it was aired.