Williams was born in Portsmouth, England and attended King's College London, graduating with a first-class LLB degree in 1984.

[1][2] She was called to the bar at Gray's Inn in 1985 and was in practice from 1987, specialising in civil liberties, judicial review and employment discrimination; she practised from and was deputy head of chambers of Doughty Street Chambers.

[3] She appeared before the inquests into the Hillsborough disaster and was successful in Miriam O'Reilly's age discrimination case against the BBC.

[1][4][2] On 1 October 2021, Williams was appointed a judge of the High Court and assigned to the Queen's Bench Division.

[1] On 1 January 2023, she became President of the Upper Tribunal (Administrative Appeals Chamber)[6] In 1997, she married Trevor Bragg and together they have a son and a daughter.