By decree of Pope Pius IX (Universalis Ecclesiae), this entity gained its elevation to the rank of a metropolitan diocese (instead of archdiocese) on 29 September 1850.

Cardinal Murphy-O'Connor had announced on 9 July 2007 that, in accordance with the age limit of 75 years prescribed for bishops in the 1983 Code of Canon Law, he had submitted his resignation to Pope Benedict XVI, but that the Pope had asked him to continue in his pastoral ministry as archbishop beyond the age limit until further provision was made, as occurred in 2009.

One of the auxiliary bishops serves as chancellor and moderator of the metropolitan curia; one as vicar for the clergy; one for pastoral affairs; and one for education and formation.

[1] Liturgy in the diocese is primarily based around the ordinary form of the Roman Rite, promulgated by Pope Paul VI, now in its third edition.

There are also a large number of Masses for the expatriate Polish community; as well as dedicated French, German, Italian, Portuguese and Spanish language churches.

There are also ethnic chaplaincies serving Catholics from Africa, Albania, Brazil, the Caribbean, China, Croatia, the Philippines, India, Hungary, Ireland, Korea, Latin America, Lithuania, Malta, Portugal, Romania, Slovakia, Czechia, Slovenia, Sri Lanka, Traveller, Gypsy and Roma communities, and Vietnam.

Religious orders of men include: the Assumptionists at Bethnal Green, Hitchin and Burnt Oak; the Augustinians at Hammersmith and Hoxton; the Augustinian Recollects at Kensal New Town, Kensington and Wembley; the Benedictines at Ealing Abbey and Cockfosters; the Carmelites at Finchley East; Discalced Carmelites at Kensington; the Christian Brothers at Twickenham; the missionary Columban Fathers at Hampstead; the Dominicans at Haverstock Hill; the Franciscans at Pimlico; the Franciscan Friars of the Atonement in Westminster; the Holy Ghost Fathers at New Barnett and Northwood; and the Passionists at Highgate.

The Jesuits have a large presence in London with communities in Mayfair (at Farm Street), Southall, Stamford Hill, Swiss Cottage, and Wimbledon.