As a youth at Eton College, he had claimed "that his father was an eminent Turkey merchant"[1] implying that, rather than a dealer in poultry, he traded with the Eastern Mediterranean.

[2] The excitement created by the actions of John Wilkes led Horne into politics, and in 1765 he brought out a scathing pamphlet on Bute and Mansfield, entitled "The Petition of an Englishman".

With inexhaustible energy he promoted the legal proceedings over the riot in St George's Fields when a youth named Allen was killed, and exposed the irregularity in the judge's order for the execution of two Spitalfields weavers.

His dispute with George Onslow, MP for Surrey, who at first supported and then threw over Wilkes for place, culminated in a civil action, ultimately decided, after the reversal of a verdict which had been obtained through the charge of Lord Mansfield, in Horne's favour, and in the loss by his opponent of his seat in parliament.

His friend William Tooke had purchased a considerable estate, including Purley Lodge, south of the town of Croydon in Surrey.

Horne, thereupon, by a bold libel on the Speaker, drew public attention to the case, and though he himself was placed for a time in the custody of the serjeant-at-arms, the clauses which were injurious to the interest of Tooke were eliminated from the bill.

For his conduct in signing the advertisement soliciting subscriptions for the relief of the relatives of the Americans "murdered by the king's troops at Lexington and Concord," he was tried at the Guildhall on 4 July 1777, before Lord Mansfield, found guilty, and committed to the King's Bench Prison in St George's Fields, from which he only emerged after a year's durance, and after a loss in fines and costs amounting to £1,200.

[2] At the general election of 1790, Horne Tooke stood as a candidate for the Westminster constituency, in opposition to Fox and Lord Hood, but was defeated.

In the meantime, the excesses of the French republicans had provoked reaction in England, and the Tory ministry adopted a policy of repression.

The ministry of Addington would not support this suggestion, but a bill was at once introduced by them and carried into law, which rendered all persons in holy orders ineligible to sit in the House of Commons, and Horne Tooke sat for only that parliament.

[2] The last years of Horne Tooke's life, from 1792 until his death in 1812, were spent in retirement, at Chester House on the west side of Wimbledon Common.

[7] The traditions of Horne Tooke's Sunday parties lasted unimpaired up to this point, and the most pleasant pages penned by his biographer describe the politicians and the men of letters who gathered around his hospitable board.

Horne Tooke's conversational powers rivalled those of Samuel Johnson; and, if more of his sayings have not been chronicled for the benefit of posterity, the defect is due to the absence of a James Boswell.

He is the subject of Coleridge's poem "Addressed to J. Horne Tooke and the Company Who Met on June 28, 1796 to Celebrate His Poll at the Westminster Election".