According to the documents, Mussolini got his start in politics in 1917 with the help of a 100 pounds weekly wage from MI5 -- 6,000 pounds today -- to write pro-war propaganda for his newspaper 'Il Popolo d'Italia' and keep Italian troops fighting at the front.
Historians in Cambridge, led by Peter Martland, have uncovered the details of the lucrative deal struck between a young Benito Mussolini and MI5, more than 64 years after his death, 'The Times' reported.
"Mussolini wasn't exactly house-trained. We know he was a womaniser par excellence. There's the potential that a lot of money was spent on that," Martland was quoted by the British newspaper as saying.
In fact, the deal was brokered by British Member of Parliament Sir Samuel Hoare, who would almost two decades later become Foreign Secretary; but in the autumn of 1917 was acting as MI5's man in Italy, according to the documents.
The hope was that Mussolini's newsprint would reach the disgruntled masses of industrialised workers, halt the strikes and overturn pacifism -- propaganda might stiffen Italy's resolve and banish the Bolsheviks.
It is unlikely that the man and Il Duce ever met, but the historians have estimated that the over-inflated wage was small beer for British budgets, from which the war was leeching 4 million pounds every day.
"This is not some Mickey Mouse back-of-an-envelope job. But what the hell do you do if you're losing a war? You keep your enemies going and 100 pounds is nothing," Martland was quoted as saying.
However, the two men went their separate ways after the armistice -- Mussolini to establish a bloody fascist dictatorship, and Hoare to work his way through the ranks of government. The two came together again in 1935 when the British foreign secretary signed the Hoare-Laval Pact, and gave his old payee control of Abyssinia.