The Cathedral Church of St. John the Evangelist is the mother church of the Portsmouth Diocese and the seat of the Catholic Bishop of Portsmouth. It was dedicated on 10 August 1892.
The diocese is within the Metropolitan Province of Southwark. It includes the whole of Hampshire, the Isle of Wight, and the Channel Islands, and also parts of Oxfordshire, Berkshire, and Dorset, stretching from Abingdon, Oxfordshire, in the north to the island of Jersey.
