William Baillie of Polkemmet, descended from an ancient family of Linlithgowshire, was the eldest son of Thomas Baillie, W.S. He was educated for the bar, aud passed advocate in 1758. He acted as Sheriff-Depute of the before-mentioned county for above twenty years ; and in 1792 was promoted to the bench. He was zealous in the discharge of the important duties of his office till within a very few years of his death, when he resigned his gown and retired from the bustle of public life, to spend the remainder of his days in quietness with his family, and to enjoy the society of a very few of the devoted friends of his early years.

His lordship is said to have owed his preferment to Lord Braxfield, who had been his professional adviser in a suit in which he was engaged as to the succession to an estate of some value. His opponent had offered liberal terms of compromise, which, by the advice of Lord Braxfield, were rejected—unfortunately, as it happened, for his client was ultimately unsuccessful. As he thought himself the cause of his friend's suffering a considerable loss, he did all he could to repair it, by procuring for him a seat on the bench. Braxfield, though he loved his friend, loved his joke too; and as Baillie was not an orator, some one having objected to the appointment very strongly, especially on that ground, Braxfield replied, "Nonsense, man; I've bargained that he's never to speak." A very clever imitation of Lord Polkemmet's judicial style is given in the celebrated Diamond Beetle Case, a jeu d'esprit by a most accomplished individual, now one of the Senators of the College of Justice.

Lord Polkemmet, while on the bench, was remarkable for his good nature. Although not considered as a first rate lawyer, or at all fitted to solve difficult legal questions, he had a fund of good sense, which, in the great mass of cases, enabled him to discharge his judicial duties with propriety. His lordship not unfrequently used the broad Scottish dialect when addressing counsel. Upon one occasion, Henry Erskine had been heard at very great length in a case—a presumption that it was not a very good one, as he was not accustomed to waste his time in idle harangue (as is too much the practice now-a-days) when he had the right side of a cause. The judge was somewhat mystified by this, as he thought, uncalled for piece of declamation. He shrewdly suspected that it was a regular attempt to bamboozle; but he was not to be done. At the termination of the pleading he observed—"A vera fine speech, Harry—vera; but I'll just mak' it play wimble-wamble in my wame o'er my toddy till the morrow." He accordingly made (to use the ordinary legal phrase) avizandum—in other words, took the process home, and returned it in due time, with an interlocutor (decision)—showing that the lawyer's eloquence had been in vain expended.

He was remarkable for the length of his fingers, and at the impugning of the Theses, which takes place in presence of the judges, the candidate for legal honours, was certiorated of the proper season to put on the cocked hat used on such occasions, by his lordship holding up his first gigantic digit. He, in consequence, was good-naturedly termed by the bar, with the members of which he was a great favourite, the "Judicial Fugleman."

Lord Polkemmet was twice married; first to a daughter of Sir James Colquhoun of Luss, Bart., by whom he had a large family, five of whom—one son and four daughters—are alive. He married, secondly, Miss Janet Sinclair, a sister of Sir John Sinclair, Bart., and cousin-german to his first wife. She had no family, and died in 1834.