In 1861 Severn was appointed British Consul in Rome during the ferment over Italian unification. A few months before his arrival Garibaldi had seized the Kingdom of Naples, and all of Southern Italy and Sicily had been annexed to the new Kingdom of Italy. Many of the kingdoms, principalities and dukedoms in the Italian peninsula had come together under the leadership of Victor Emmanuel II, but Rome and its surroundings remained as the rump of the Papal States. This was the case throughout the majority of Severn's tenure as Consul, as Pope Pius IX managed to retain a fragile hold on power, relying on a garrison of French troops to control Rome. Although the official position of the British government on "The Roman Question" was neutrality and nonintervention, Severn often took diplomatic action that his superiors viewed as exceeding his mandate as Consul. On several occasions, such as when he used his office to liberate Italian political prisoners in 1864, he was rebuked by the Foreign Office. His knowledge of the Italian language and his affability and good humor, however, often helped in mediating between the papal regime and the British government, and he was able on many occasions to offer advice and protection for British visitors who found themselves in awkward scrapes. He eventually retired as Consul in 1872.