The Lords Spiritual of the United Kingdom, also called Spiritual Peers, are the 26 bishops of the established Church of England who serve in the House of Lords along with the Lords Temporal. The Church of Scotland, which is Presbyterian, and the Anglican churches in Wales and Northern Ireland, which are no longer established churches, are not represented by spiritual peers.
The Church of England comprises 42 dioceses, each led by a diocesan bishop. The diocesan bishops of Canterbury and York are archbishops, who also have oversight over their respective provinces. The occupants of the five "great sees"—Canterbury, York, London, Durham and Winchester—are always spiritual peers and Lords of Parliament. The Bishop of Sodor and Man and the Bishop of Gibraltar in Europe may not sit in the House of Lords regardless of seniority as their dioceses lie outside the United Kingdom. (The former, however, sits on the Legislative Council of the Isle of Man ex officio.) Of the remaining 35 bishops, the 21 most senior sit in the House of Lords. Seniority is determined by total length of service as an English diocesan bishop (that is to say, it is not lost by translation to another see).