The Diocese of Gibraltar is a Latin Church diocese of the Catholic Church in the British overseas territory of Gibraltar. About twenty priests and nine sisters serve in the diocese. Carmelo Zammit was installed as bishop on 24 September 2016. At just over 6 square kilometers, it is among the smallest of all Catholic dioceses in the world.

The Apostolic Nunciature to Great Britain is the diplomatic office of the Holy See in Great Britain. It is headed by the Apostolic Nuncio, who has the rank of an ambassador. The parties agreed to exchange representatives at the ambassadorial level and Pope John Paul II erected the Nunciature to Great Britain on 17 January 1982. Before then, the interests of the Holy See in Great Britain had been represented by an Apostolic Delegate since 1938, though not granted diplomatic status until 1979. The decision to designate the nuncio to Great Britain rather than the United Kingdom reflected the complex and frequently antagonistic relationship between the Holy See and the British crown since they severed ties in the sixteenth century. British government sources said it had been agreed that the nuncio in London would concern himself with matters in England, Scotland and Wales, while the Apostolic Nuncio to Ireland, based in Dublin, would have within his purview the entire island of Ireland.