Hereditary peerage subsidiary to another created by the same letters patent
Peerages of this type
| Title | Letters patent | Extinct | Merged into crown |
|---|---|---|---|
| Milton (Barony) | 9 April 1689 | - | - |
| Milton (Viscountcy) | 21 July 1716 | - | - |
| Milton (Viscountcy) | 6 September 1746 | - | - |
| Milton (Viscountcy) | 18 May 1792 | - | - |
| Molesworth (Barony) | 16 July 1716 | - | - |
| Monck (Barony) | 7 July 1660 | 6 October 1688 | - |
| Monson (Barony) | 23 August 1628 | - | - |
| Montagu (Barony) | 12 July 1660 | - | - |
| Montgomery (Viscountcy) | 24 March 1687 | 8 March 1748 | - |
| Monthermer (Viscountcy) | 9 April 1689 | - | - |
| of Monthermer (Marquessate) | 5 November 1766 | - | - |
| of Monthermer (Marquessate) | 14 April 1705 | - | - |
| Mordaunt (Barony) | 10 July 1659 | - | - |
| Morpeth (Viscountcy) | 20 April 1661 | - | - |
| Mountcastle (Barony) | 2 December 1701 | - | - |
| Mount Charles (Viscountcy) | 21 November 1797 | - | - |
| of Mount Charles (Earldom) | 15 January 1816 | - | - |
| Mountjoy (Viscountcy) | 1 March 1796 | - | - |
| Moyorta (Barony) | 17 July 1662 | - | - |
| of Munster (Earldom) | 20 May 1789 | - | 26 June 1830 |