Downton was a parliamentary borough in Wiltshire, which elected two Members of Parliament (MPs) to the House of Commons from 1295 until 1832, when it was abolished by the Great Reform Act.
On 11 June 1826 the poet Southey was elected MP for Downton, but he did not take his seat when Parliament assembled in July, and in November wrote to the Speaker: "Having while I was on the continent been, without my knowledge, elected a burgess to serve in the present Parliament for the borough of Downton, it has become my duty to take the earliest opportunity of requesting you to inform the honourable House that I am not qualified to take a seat therein, inasmuch as I am not possessed of such an estate as is required by the Act passed in the ninth year of Queen Anne."
However, the Earl of Radnor pushed for its complete disfranchisement as it would be too difficult to make even an extended borough free of the influence of himself and his family.
As this abolition of a Whig-owned borough was useful to the Whig government in demonstrating their even-handedness, they backed an amendment to move Downton into Schedule A, the list of boroughs that were to lose both seats; but the government majority in the Commons fell to 30 in the vote on the amendment, the narrowest of all the votes on the details of the eventual Act.
The Reform Act being passed, Downton ceased to be represented from the 1832 general election, those of its residents who were qualified voting instead in the county constituency of Southern Wiltshire.