Journalist; b. Maghera, Ireland, Nov. 17, 1858; d. London, Feb. 19, 1934. Early in life Diamond migrated to England and settled among the large working-class population of Irish immigrants in Newcastle-upon-Tyne. In this environment he grew deeply interested in Irish nationalist politics. He was elected Member of Parliament for North Monaghan (1892), but the absorbing interest of his life was Catholic journalism. He founded the Irish Tribune (1884) to champion the cause of the immigrants in industrial Tyneside and developed the New Catholic Press Ltd. In 1887 he was invited to Glasgow to help the group of Irish immigrants who had launched the Glasgow Observer. He bought the paper in 1894 and established the Scottish Catholic Printing Co. Ltd., which published local editions of the paper in other parts of Scotland, such as the Edinburgh Catholic Herald, the Lanarkshire Catholic Herald, and the Clydesdale Catholic Herald. He adopted the same policy in England, where the parent paper was the London Catholic Herald.
In addition to these newspapers, Diamond sponsored weekly and monthly journals and is reputed to have controlled more than 40 publications, covering all the areas of Scotland and England where Irish immigrants had settled in large numbers. He was a vigorous writer in the cause of Irish nationalism; the policies of his newspapers won the sympathies of the expatriated Irish of Great Britain and, in particular, they encouraged the flow of money and material from the Irish immigrants in southwest Scotland to make possible the success of the Sinn Fein campaign in Ireland. An article he wrote in December 1919 on the ethics of tyrannicide brought him a six-month jail sentence. His benefactions toward the social and educational improvement of Catholics increased with advancing years, and his journalistic activities continued until his death.