An early draft of the King's Speech reveals Britain was ready to declare war on Germany a week before Hitler invaded Poland.
The draft of the King George VI first wartime radio broadcast, which has come to light for the first time 74 years after it was written, is dated August 25, 1939 – seven days before Germany crossed the border into Poland
The speech – depicted in the 2010 movie The King's Speech starring Colin Firth as the stammering monarch – opened with the line “In this grave hour, perhaps the gravest in our history ...”
The three page document, entitled 'Draft King's Speech', accused Germany of being a bully that wanted to dominate the world by brute force, stressing that “we are fighting for the principles of freedom and justice.”
The typed document is an edited version of the first draft which had been written by civil servant Harold Vale Rhodes.
He kept held of the copy of his amended speech and in a pencilled note in the left hand margin criticised the length of some of the sentences, hinting that his copy should be used.
It would appear his advice was followed as the final speech read out live to the nation and the Commonwealth by the King on September 3 contained short, concise sentences.
Although the tone remained the same, some of the content was significantly different as the draft did not mention Germany or Hitler by name but merely “our enemies.”
The intermediate, rejected draft was acquired by the unnamed owner in a load of paperwork from Mr Rhodes' estate following his death in 1970.
It has now been put up for sale at auction with a pre-sale estimate of £4,000.
Hindsight tells us that Britain had been expecting war with Germany since Hitler broke various conditions of the 1919 Treaty of Versailles, such as the rebuilding the armed forces in 1935.
In 1938 he annexed Austria into Nazi Germany and invaded Czechoslovakia.
But it was after Hitler invaded Poland that Britain officially declared war on Germany on September 3, 1939.
In the Oscar winning film, Colin Firth's royal character was given little time to prepare for his defining address to the nation but in reality it appears the speech was being readied over a week beforehand.
Dr Gabriel Heaton, of auctioneers Sotheby's which is selling the speech, said: "This is a fascinating document for a number of reasons.
"It brings to life not just the speech but a pivotal moment in British history.
"It was written before Poland had been invaded but at a time when it was clear we were moving towards war with Germany.
"It shows that something was being prepared days in advance of the declaration of war so that the monarch had a speech ready in order to speak to the nation and the Commonwealth.
"You get a sense of the preparations for the speech and the struggle to find the right words to prepare the nation for the terrible fight that lay ahead.
"There would have been a group of people writing this speech and Rhodes was one of them.
"He had provided a first draft and was sent this revised version. His note in the margin is saying that his original is better than this one and that the wording should be shorter.
"The final version was a lot clearer. The sentences were shorter and the structure was simpler and that is what you want for public speaking, especially when the speaker has a speech impediment."
Nigel Steel, a historian at the Imperial War Museum, said: "When it happened, war wasn't out of the blue.
"There had been a number of political crises involving Germany going on for over a year before.
"The idea that this speech was prepared in advance of war is not a huge surprise, especially as the King had difficulties in delivering speeches."
The auction takes place at Sotheby's in London on December 10.