Sir Alan Lascelles was King George VI's private secretary from 1943-52.
Lascelles, in his diaries, entitled King's Counsellor, wrote that, in June 1944, General Georges Catroux, of the Free French forces, had asked the British government's Alfred Duff Cooper "to see a certain French officer, urgently."
The diary entry for 21 June 1944 continues: "This man, who is a very big noise in the French intelligence service, told Duff that he had very reliable information that Hitler had fled from Berlin to a villa near Perpignan, where he is now hiding and waiting a favourable opportunity to slip across the Spanish frontier."
By 1944, Hitler no longer appeared in public. (20 July plot - Wikipedia, the free encyclopedia)
Why might Hitler have wanted to leave Germany in 1944?
According to Lascelles, Germany talked of peace terms as early as 1943.
In his diary entry for 27 december 1943, Lascelles wrote: "Hughe Knatchbull-Hugessen telegraphed yesterday from Ankara that Numan (Turkish Foreign Minister) had told him ... that the German Minister in Bucharest had called (in uniform) on the Romanian Foreign Minister, and told him Germany would accept peace on the following terms: they would surrender fleet, submarines, merchant fleet, air force, disarm completely, evacuate all occupied territory, undertake never to ask for colonies, and leave Europe to be organised according to the wishes of the Allies.
"The only condition they asked for is economic freedom for Germany, but this is to be arranged as found suitable by the Allies."
Roosevelt and Churchill insisted on unconditional surrender.
And this worked to the advantage of Russia, which ened up controlling Eastern Europe (The Price We Paid for Roosevelt's "Unconditional Surrender").
In 1943, sections of the German military showed signs of wanting rid of Hitler.
Between 1943 and March 1944 there were seven plots against Hitler. (Axis History Factbook: Assassination Plots & Attempts)
The 20th July 1944 plot failed to kill Hitler, or his 'double'.
Journalist Abel Basti says Hitler escaped from Spain by submarine into exile in South America.
He claims to have a document showing the FBI searched for the Hitler in Spain in 1947. (Adolf Hitler 'fled into exile' - The Sunday Mail )
If Hitler fled from Berlin in June 1944, then who was acting as his 'double' back in Germany, up until April 1945, when Hitler supposedly died.
Is this Hitler's 'double'?
According to Time magazine, in 1935: "Adolf Hitler last week became the first Dictator frankly to employ a double.
"Impersonating the Realmleader, a pudgy-fingered, smudge-mustached person officially opened the new motor highway from Holzkirchen to Munich.
"Suddenly the crowd recognized Dictator Hitler standing unobtrusively a few yards from his double and good-natured German cheers were given first for one, then for the other." (GERMANY: Double Hitler - TIME)
Reportedly, the Russians found the corpse of Adolf Hitler's double near Hitler's bunker.
In November 1944, the Daily Express published photos of Hitler 'past' and 'present', suggesting that the 'present' Hitler was not the real Hitler.
The Express pointed out that the ears on the 'present' Hitler were different from the ears on the 'past' Hitler.
The Daily Express, according to Sir Alan Lascelles in his diary entry of 23 November 1944, "proves fairly conclusively" that the man in the recent photos "cannot be the real Hitler."