He left Edinburgh with very mixed feelings, for he hated the place and loved its inhabitants. He called it "that energetic and unfragrant city." He dwelt in memory on its "odious smells, barbarous sounds, bad suppers, excellent hearts, and most enlightened and cultivated understandings."

"No nation," he said, "has so large a stock of benevolence of heart, as the Scotch. Their temper stands anything but an attack on their climate. They would have you even believe they can ripen fruit; and, to be candid, I must own in remarkably warm summers I have tasted peaches that made most excellent pickles; and it is upon record that at the Siege of Perth, on one occasion the ammunition failing, their nectarines made admirable cannon-balls. Even the enlightened mind of Jeffrey cannot shake off the illusion that myrtles flourish at Craig Crook.[22] In vain I have represented to him that they are of the genus Carduus, and pointed out their prickly peculiarities…. Jeffrey sticks to his myrtle illusions, and treats my attacks with as much contempt as if I had been a wild visionary, who had never breathed his caller air, nor lived and suffered under the rigour of his climate, nor spent five years in discussing metaphysics and medicine in that garret of the earth—that knuckle-end of England—that land of Calvin, oatcakes, and sulphur."

As soon as he reached England, he wrote to his friend Jeffrey:—

"I left Edinburgh with great heaviness of heart; I knew what I was leaving, and was ignorant to what I was going. My good fortune will be very great, if I should ever again fall into the society of so many liberal, correct, and instructed men, and live with them on such terms of friendship as I have done with you, and you know whom, at Edinburgh."

On arriving in London, in the autumn of 1803, the Sydney Smiths lodged for a while at 77 Upper Guilford Street, and soon afterwards established themselves at 8 Doughty Street. Sydney's dearest friend, Francis Horner,[23] had preceded him to London, and was already beginning to make his mark at the Bar, without, apparently, abandoning his philosophical pursuits. "He lives very high up in Garden Court, and thinks a good deal about Mankind." But he could spare a thought for individuals as well as for the race, and did a great deal towards securing his friend an introduction into congenial society. Doughty Street was a legal quarter, and among those with whom the Smiths soon made friends were Sir Samuel Romilly, James Scarlett (afterwards Lord Abinger), and Sir James Mackintosh. To these were added as time went on, Henry Grattan, Alexander Marcet, John William Ward (afterwards Lord Dudley), Samuel Rogers, Henry Luttrell, "Conversation" Sharp, and Lord Holland.

Sydney Smith's eldest brother Robert ("Bobus"[24]) had married Caroline Vernon, Lord Holland's aunt. Sydney's politics were the politics of Holland House. Lord Holland was always recruiting for the Liberal army, and an Edinburgh Reviewer was a recruit worth capturing. So the hospitable doors were soon thrown open to the young clergyman from Doughty Street, who suddenly found himself a member of the most brilliant circle ever gathered under an English roof. In old age he used to declare, to the amusement of his friends, that as a young man he had been shy, but had wrestled with the temptation and overcome it. As regards the master[25] of Holland House, it was not easy to be shy in the presence of "that frank politeness which at once relieved all the embarrassment of the youngest and most timid writer or artist, who found himself for the first time among Ambassadors and Earls."[26] And even the imperious mistress[27] of the house found her match in Sydney Smith, who only made fun of her foibles, and repaid her insolence with raillery. Referring to this period, when he had long outlived it, he said:—

"I well remember, when Mrs. Sydney and I were young, in London, with no other equipage than my umbrella, when we went out to dinner in a hackney coach (a vehicle, by the bye, now become almost matter of history), when the rattling step was let down, and the proud, powdered red-plushes grinned, and her gown was fringed with straw, how the iron entered into my soul."

One of the most useful friends whom the Smiths discovered in London was Mr. Thomas Bernard,[28] afterwards a baronet of good estate in Buckinghamshire, and a zealous worker in all kinds of social and educational reform. Mr. Bernard was Treasurer of the Royal Institution in Albemarle Street, which had been founded in 1799; and, with the laudable desire of putting a few pounds into a friend's pocket, he suggested that Sydney Smith should be invited to lecture before the Institution. The invitation was cordially given and gratefully accepted. The lecturer chose "Moral Philosophy" for his subject, and the Introductory Lecture, in which he defined his terms, was delivered on the 10th of November 1804. The second and third lectures dealt with the History of Moral Philosophy; the fourth, with the Powers of External Perception; the fifth, with Conception; the sixth, with Memory; the seventh, with Imagination; the eighth, with Reason and Judgment; and the ninth, with the Conduct of the Understanding.

These lectures were treated by the author as forming one course, their general subject being "The Understanding." In February 1805 he wrote to his friend Jeffrey:—"I got through my first course I think creditably; whether any better than creditably others know better than myself. I have still ten to read." This second course followed immediately on the first, and, under the general head of "Taste," discussed topics so various as "Wit and Humour," "The Beautiful," "The Sublime," "The Faculties of Animals as compared with those of Man," and "The Faculties of Beasts." By this time the lectures had become fashionable. One eye-witness writes:—

"All Albemarle Street, and a part of Grafton Street, was rendered impassable by the concourse of carriages assembled there during the time of their delivery. There was not sufficient room for the persons assembling; the lobbies were filled, and the doors into them from the lecture-room were left open."