1818 Horner was MP for
St. Ives in 1806,
Wendover in 1807, and
St. Mawes in 1812 (in the patronage of the
Marquess of Buckingham). He translated
Leonhard Euler's
Elements of Algebra in 1797 and revised Henry Bennet's
Short Account of a late Short Administration for publication in 1807. Horner was offered a
Treasury secretaryship in 1811 when
Lord Grenville was attempting to form a ministry, which he refused as he would not accept office until he was wealthy enough to survive out of office. A believer in
political economy, he criticised the
Corn Laws and slavery in 1813–15. On 20 March 1815 the City of London voted thanks to him for his critique of protectionism. where he "extended and confirmed his fame as a political economist by his share in the famous
Bullion Report". The committee produced its report on 8 June (but not published until August). On 20 February 1811 Horner advocated the repeal of restrictions on cash payments and on 6 May put forward sixteen resolutions in favour but they were countered on 26 June by government counter-resolutions. In January 1811 Horner wrote: In the situation to which the continent of Europe is reduced, and in the situation which England commands, I cannot imagine a general peace of any duration; and without it, we can have no peace with France ... If the whole Continent were to be tranquillised into one empire, and should slumber for years in repose under a vigilant and well-organised despotism, no fate could be intended for us but annexation to the mass; nor could we devise any safety for ourselves, but by adopting public institutions, and by fostering sentiments of individual ambition and conduct, of which defensive war and the most rigid prejudices of local patriotism were constant objects ... It seems infinitely more probable, that the new empire of France will be perpetually disturbed by efforts in one member or another to throw off the yoke ... I conceive it would be the duty of this country ... to contribute from our resources every aid and encouragement to the insurgents. It is idle to sigh for peace, if it cannot be had upon system, and for a period to be sure of; England forms a part of Europe, and must share its vicissitudes and agitations. Horner further claimed that the British war policy should be based on "the principles by which
Elizabeth was guided, and afterwards
King William; forbearing all little bye objects of gain and aggrandisement, and keeping steadily in view, through all fortunes and in the lowest depth of our despair, the ultimate partition of the Continent into independent states, and the revival of a public law in Europe". After Napoleon's defeat in 1814, he criticised the peace settlement as "the plunder of Europe" by the "robbers of
Vienna". After Napoleon escaped from Elba and became ruler of France again, Horner was against the resumption of war and the tax burden needed to pay for it. He also opposed the Bourbon restoration in France and Naples. This led to disagreements with the Grenvillite faction and on 8 April he offered to resign his seat but was persuaded not to by Lord Grenville. On 28 April he voted for Samuel Whitbread's peace motion and again considered resignation but decided not to. After Napoleon's defeat he again opposed a conservative peace settlement, the expensive military establishment and the heavy tax burden that it entailed. Horner's proposed Bill for regulation grand juries on indictments in Ireland was passed in 1816 and
Grand Jury (Ireland) Act 1816 became law. His proposal on 1 May to end the renewal of the
Bank Restriction Act 1797 was defeated in the Commons by 146 votes to 73, as was his proposals to authorise cash payments in two years' time. ==Death==