Sir Robert Dallas, PC, SL KC (16 October 1756 – 25 December 1824) was an English judge, of a Scottish family.
Robert Dallas was born at [St. Michael's, Cornhill, London], in 1756. Dallas and his brother George were educated first at James Elphinstone's school in Kensington, and then in Geneva, by the pastor Chauvet. He entered Lincoln's Inn on 4 November 1777. During this period, he honed his facility of oratory at the public debates in Coachmaker's Hall, where he was known for his extensive general knowledge and his politeness.
Called to the bar on 6 November 1782, Dallas soon built a considerable practice, and specialized in parliamentary and privy council cases. In 1783, he was retained as junior counsel by the British East India Company to challenge the East India Bill.
Dallas's most notable accomplishment, perhaps, was to come in 1787, when he served as junior counsel for the defence in the Impeachment of Warren Hastings. Hasting's defence, led by Edward Law and seconded by Dallas and Thomas Plumer, formed a particularly able and harmonious legal team, and many of his contemporaries praised Dallas's exertions during the seven-year case. Hastings was exonerated in 1795, and Dallas took silk on 2 March 1795 and was elected a bencher of Lincoln's Inn on 23 April 1795.
Dallas continued to enjoy an active practice, receiving numerous briefs to assist parliamentary committees in investigating disputed elections. He briefly entered the House of Commons himself from 1802 until 1805 as Member of Parliament for the rotten borough of Mitchell, resigning in February 1805 to accept the office of Chief Justice of Chester. He re-entered Parliament in March, representing Dysart Burghs, but left that seat in 1806. While little active in the Commons, he was considered a useful supporter of Addington.