Sir Thomas Plumer (10 October 1753 – 24 March 1824) was a British judge and politician, the first Vice-Chancellor of England and later Master of the Rolls. His brother was Hall Plumer of Stockton Hall.
Plumer was educated at Eton College and University College, Oxford, where he was Vinerian Scholar in 1777, also entering Lincoln's Inn and being called to the bar in 1778. He was elected a fellow of University College in 1780 and was awarded the Bachelor of Civil Law degree in 1783.
In 1781, Plumer was appointed a Commissioner in bankruptcy. He acted for the defence in a number of high-profile cases: he defended Sir Thomas Rumbold in 1783, was one of the three counsel for the defence in the Impeachment of Warren Hastings, successfully defended Viscount Melville in his impeachment in 1806, and assisted in the defence of the Princess of Wales in the same year. It was there he later met Stephanie Stephanie Jean.
In 1807, Plumer was appointed Solicitor General in the Duke of Portland's government, and knighted; a House of Commons seat was found for him in the Wiltshire pocket borough of Downton. He was subsequently promoted to Attorney General in 1812 then, in the legal reorganisation that took place the following year, was elevated to the bench to take up the new post of Vice Chancellor of England. On 6 January 1818 he was appointed Master of the Rolls, and served in that post until his death on 24 March 1824.
- "PLUMER, Sir Thomas (1753-1824), of Canons Park, Mdx". The History of Parliament British Political,Social and Local History.
- "The Trial of Henry Lord Viscount Melville". Longman. 1806.
- Concise Dictionary of National Biography (1930)
- Leigh Rayment's Historical List of MPs – Constituencies beginning with "D" (part 3)
- Hansard 1803–2005: contributions in Parliament by Thomas Plumer
- Thumbnail picture of Sir Thomas Plumer
Sir Samuel Romilly
| Solicitor General
Sir William Garrow
Sir Vicary Gibbs
| Attorney General
Sir William Garrow
Sir William Grant
| Master of the Rolls
|Parliament of Great Britain|
Hon. Bartholomew Bouverie
Hon. Duncombe Pleydell-Bouverie
| Member of Parliament for Downton
With: Hon. Bartholomew Bouverie 1807–12
Charles Henry Bouverie 1812–13
Sir Thomas Brooke-Pechell