| Honorific-Prefix: | The Right Honourable |
| The Lord Williams of Mostyn | |
| Honorific-Suffix: | PC QC |
| Office: | Leader of the House of Lords |
| Primeminister: | Tony Blair |
| Term Start: | 8 June 2001 |
| Term End: | 20 September 2003 |
| Predecessor: | The Baroness Jay of Paddington |
| Successor: | The Baroness Amos |
| Office1: | Lord President of the Council |
| Primeminister1: | Tony Blair |
| Term Start1: | 13 June 2003 |
| Term End1: | 20 September 2003 |
| Predecessor1: | John Reid |
| Successor1: | The Baroness Amos |
| Office3: | Lord Keeper of the Privy Seal |
| Primeminister3: | Tony Blair |
| Term Start3: | 8 June 2001 |
| Term End3: | 13 June 2003 |
| Predecessor3: | The Baroness Jay of Paddington |
| Successor3: | Peter Hain |
| Office4: | Attorney General for England and Wales Attorney General for Northern Ireland |
| Primeminister4: | Tony Blair |
| Term Start4: | 29 July 1999 |
| Term End4: | 8 June 2001 |
| Predecessor4: | John Morris |
| Successor4: | The Lord Goldsmith |
| Office5: | Deputy Leader of the House of Lords |
| Term Start5: | October 1998 |
| Term End5: | June 2001 |
| Primeminister5: | Tony Blair |
| Leader5: | The Baroness Jay of Paddington |
| Predecessor5: | The Baroness Jay of Paddington |
| Successor5: | The Baroness Symons of Vernham Dean |
| Office6: | Minister of State for Prisons |
| Primeminister6: | Tony Blair |
| Term Start6: | 28 July 1998 |
| Term End6: | 28 July 1999 |
| Predecessor6: | Joyce Quin |
| Successor6: | Charles Clarke |
| Office7: | Parliamentary Under-Secretary of State for Home Affairs |
| Primeminister7: | Tony Blair |
| Term Start7: | 2 May 1997 |
| Term End7: | 28 July 1998 |
| Predecessor7: | Tom Sackville |
| Successor7: | Kate Hoey |
| Office8: | Member of the House of Lords Lord Temporal |
| Term Start8: | 20 July 1992 |
| Term End8: | 20 September 2003 Life peerage |
| Birth Date: | 5 February 1941 |
| Birth Place: | Prestatyn, Wales |
| Death Place: | Evenlode, England |
| Party: | Labour |
| Alma Mater: | Queens' College, Cambridge |
| Children: | 4 |
Gareth Wyn Williams, Baron Williams of Mostyn, (5 February 1941 – 20 September 2003), was a Welsh barrister and Labour politician who was Leader of the House of Lords, Lord President of the Council and a member of the Cabinet from 2001 until his sudden death in 2003.
Williams was born near Prestatyn, in North Wales, a son of Albert Thomas Williams and his wife Selina, née Evans.[1] He was educated at Rhyl Grammar School and at Queens' College, Cambridge.[1]
He was called to the bar at Gray's Inn in 1965,[1] he became Queen's Counsel in 1978,[1] was a Recorder from 1978, a Deputy High Court Judge, 1986–92, the Leader of the Wales and Chester Circuit, 1987–89,[1] and a Member of the Bar Council, 1986-92[1] (Chairman, 1992).[1]
He was created a life peer on 20 July 1992 as Baron Williams of Mostyn, of Great Tew in the County of Oxfordshire, and became an opposition spokesman in the House of Lords on Legal Affairs, and later Northern Ireland. After Labour's election victory he was appointed a Home Office minister, and in 1999 became Attorney General for England and Wales and Northern Ireland. He was appointed Leader of the House of Lords in 2001, initially with the sinecure office of Lord Privy Seal, for which Lord President of the Council was substituted in 2003.
As part of the celebrations to mark the fiftieth anniversary of the Life Peerages Act, Lord Williams was voted by the current members of the House of Lords as the outstanding life peer since the creation of the life peerage.[2] In his book A View from the Foothills Chris Mullin wrote that he thought that Gareth Williams was most likely to succeed Derry Irvine as Lord Chancellor; in the event the position was next filled by Charles Falconer.[3]
Williams married Pauline Clarke in 1962, and they had three children. They divorced, and he then married Veena M. Russell in 1994, and by her had one daughter, Imogen.[1] He died from a heart attack at his home in Evenlode, Gloucestershire on 20 September 2003, aged 62, and was buried at St Michael and all Angels Church in Great Tew, Oxfordshire.[4]
| Escutcheon: | Ermine on a pile flory at the point Sable a lion rampany Or armed and langued Gules. |
| Crest: | A portcullis Or in front of an arm embowed vested and the cuff braided Sable frilled at the wrist the hand Proper holding by its blade upwards Argent a sword palewise to the front of the portcullis its hilt pommel and quillons Gold. |
| Supporters: | Dexter upon a grassy mount growing therefrom two sweet pea flowers Proper a griffin statant erect Gold sinister upon a like mount a dragon statant erect also Gold both armed and langued Gules. |
| Motto: | Y Gwir Yn Erbyn Y Byd[5] |
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