History remembers Benito Mussolini as the Italian dictator who ruled his country with fear and forged a disastrous alliance with Nazi Germany. But now a previously unknown area of Il Duce's CV has come to light: his brief career as a British agent.

Archived documents have revealed that Mussolini got his start in politics in 1917 with the help of a £100 weekly wage from MI5.

Mussolini, then a 34-year-old journalist, was not just willing to ensure Italy continued to fight alongside the Allies in World War I by publishing propaganda in his paper. He was also willing to send in the boys to ''persuade'' peace protesters to stay at home.

Mussolini's payments were authorised by Sir Samuel Hoare, an MP and MI5's man in Rome, who ran a staff of 100 British intelligence officers in Italy at the time.

Cambridge historian Peter Martland, who discovered details of the deal, said: ''Britain's least reliable ally in the war at the time was Italy after revolutionary Russia's pull-out from the conflict. Mussolini was paid £100 a week from the autumn of 1917 for at least a year to keep up the pro-war campaigning - equivalent to about £6000 ($A10,400) a week today.''