The Payments he received must have helped him fund the start up of his "Il Popolo d'Italia", and since his objectives were similar to the Brits, he had no compunctions of accepting "funding".

Mussolini left the International Socialists, and Editor of "Avanti" in October of 1914, and started his own newspaper "Il Popolo d'Italia". Mussolini's rift with other Socialist's, was because of his position of ACTIVE Neutrality vs their ABSOLUTE Neutrality. and then in Nov 1914, he split Entirely with them and took the Anti-Socialistic position of INTERVENTION (WAR).. WWI had started on August 1914, Italy stayed Neutral until May 23 1914, when an ill prepared Italy was lured into the War with Great Promises, that England and France reneged on at the Treaty of Versailles. Benito was called up for military service 3 months later, on August 1915, as a private, and served until his discharge in August 1917 from mortar wounds.

Actually, What is fascinating, is to try to analyze Mussolini trajectory. For his first 13 years in power he was admired by leaders of England ,France, and the US. Most people believe the History as written by the Victors, so they paint him falsely as a Right Wing Dictator, who was not replaced by a Military Coup, but was deposed at the Grand Council of Fascism. He was an Icon until 1935, when he was side swiped by Britain /France who had approved his Invasion of Ethiopia. He lid further with his Racial Laws in 1937, but was Pushed over the edge by Anthony Eden's Rejection of Mussolini's offer to become an Ally of Britain /France vs Hitler, whom he viewed as a Maniac.

Mussolini's father was an Anarchist, he was named after a Mexican Revolutionary. Benito was influenced by Internationalist Socialist, by Nationalist Socialists, by Marxism, by Syndicalists, and was Anti-Colonialist. 
His regime has been described as a Dictatorship, Corporate-Statism, Welfare Capitalism, etc. Since he had such a varied Leftist background, people found it difficult to "pigeon hole" him, or even describe him, and explained his actions as opportunistic, rather than reality driven, and non -ideologue. He clearly was a desperate and depressed man after the Rejection of Eden, and being driven into Hitler's Arms.

Mussolini, MI5's Man in Italy
ABC News;By Europe Correspondent Emma Alberici; Thu Oct 15, 2009  

Historians have discovered that Italy's notorious fascist dictator Benito Mussolini worked for the British secret services during World War I.

Cambridge University historian Dr Peter Marland says MI5 records show that the organisation paid Mussolini 100 pounds a week to spread pro-war propaganda in Italy via his newspaper.

In todays terms, the payments to Benito Mussolini would be worth $8,700 a week.

The discovery was made after studying the papers of former MI5 agent Sir Samuel Hoare.

Sir Samuel went on to become foreign secretary almost two decades later, and in 1935 signed the pact that would give Mussolini control over Abyssinia, the country that is now Ethiopia.

http://www.abc.net.au/news/stories/
2009/10/15/2714586.htm?section=world

Benito Mussolini was born into a working class background; his father Alessandro Mussolini was a blacksmith and an Anarchist activist, Mussolini was named Benito after Mexican reformist President Benito Juárez, while his middle names Andrea a nd Amilcare were from Italian socialists Andrea Costa and Amilcare Cipriani. Alessandro was a socialist, but also held some nationalistic views, especially in regards to some of the Italians who were living under the rule of the Austro-Hungarian Empire,which were not consistent with the internationalist socialism of the time. 

Mussolini qualified as an elementary schoolmaster in 1901. In 1902, Mussolini emigrated to Switzerland.He worked as a stone mason and during this time studied the ideas of Nietzche, the sociologist Pareto and the syndicalist Sorel. Mussolini also, later in life, credited as influences on his thought the French Marxian Convert Charles Péguy and Hubert Lagardelle (also a French Syndicalist).Sorel's emphasis on the need for overthrowing decadent liberal Democracy and Capitalism by the use of violence, direct action, the general strike, and the use of neo-Machiavellian appeals to emotion, impressed him deeply.

Soon he joined the Marxian Socialist movement. In February 1908 in the city of Trento as secretary of the local chamber of labor, which was ethnically Italian but then under the control of Austria-Hungary. While there he wrote The Cardinal's Mistress which was bitterly anticlerical and years later had to be withdrawn from circulation after he made his truce with the Vatican. He did office work for the local socialist party and edited its newspaper L'Avvenire del Lavoratore ("The Future of the Worker").

By 1910 Mussolini returned to Forli where he edited the weekly Lotta di classe. He was now one of Italy's most prominent Socialists. In 1911 there was a riot by Socialists, and Mussolini with them, in Forlì, against the Italian war in Libya. He bitterly denounced the "imperialist war" to gain Tripoli, and he was rewarded with the editorship of the Socialist party newspaper Avanti! Its circulation soon rose from 20,000 to 100,000. By 1913 he wrote the historically and political publication Giovanni Hus, il Veridico (Jan Hus, True prophet) about life and mission of Jan Hus and his military followers Hussite. 

In October 1914, finding himself in opposition to the directorate of the Italian Socialist party because he advocated a kind of active neutrality on the part of Italy in the War of the Nations against the party's tendency of absolute neutrality, he withdrew on the twentieth of that month from the directorate of Avanti! 

Then on the fifteenth of November [1914], thereafter, he initiated publication of the newspaper Il Popolo d'Italia in which he supported -- in sharp contrast to Avanti! and amid bitter polemics against that newspaper and its chief backers -- the thesis of Italian intervention in the war against the militarism of the Central Empires. For this reason he was accused of moral and political unworthiness and the party thereupon decided to expel him. Thereafter he....undertook a very active campaign in behalf of Italian intervention, participating in demonstrations in the piazzas and writing quite violent articles in Popolo d'Italia....

Inspector-General of Public Security in Milan, G. Gasti in a Report on Mussolini, who was considered important enough to be under constant surveillance, noted he entered the Army and served in the war. 

"He was promoted to the rank of corporal "for merit in war." The promotion was recommended because of his exemplary conduct and fighting quality, his mental calmness and lack of concern for discomfort, his zeal and regularity in carrying out his assignments, where he was always first in every task involving labor and fortitude."

"He was sent to the zone of operations where he was seriously injured by the explosion of a grenade."and totalled about nine months of active, front-line trench warfare. During this time he contracted paratyphoid fever. His military exploits ended in 1917 when he was wounded by the explosion of a mortar bomb in his trench. He was left with at least 40 shards of metal in his body. He was discharged from the hospital in August 1917, and resumed his editor-in-chief position at his new paper, Il Popolo d'Italia

http://en.wikipedia.org/wiki/Benito_Mussolini
 

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