In December 1783, George III engineered the dismissal of the Fox–North coalition, which he hated, and appointed William Pitt the Younger as Prime Minister.

By 1 March, Fox's motion which concluded by "beseech[ing] His Majesty, that He would be graciously pleased to lay the Foundation of a strong and stable Government, by the previous Removal of His present Ministers" was carried but only by 201 to 189.

Thanks to a combination of patronage and bribes paid by HM Treasury, many small pocket boroughs returned Pitt-supporting MPs as widely expected.

Fox was one of the two sitting members for the constituency of Westminster, which had the largest electorate of any in the country and a great deal of prestige.

He stood against two Pitt supporters for the constituency's two seats; both sides spent heavily, campaigned bitterly, allegedly libelled and slandered their opponents relentlessly and resorted to all kinds of tactics, including Georgiana, Duchess of Devonshire, touring the streets and, according to the opposition, kissing many voters to induce them to vote for Fox.

The process did not show unexpectedly large numbers of unqualified voters and as the months went by it looked more and more like a political delaying tactic; on 4 March 1785 the House of Commons finally put an end to it by ordering the Returning Officer to declare the result.

The election was notable for being one of the first in history in which visual propaganda, in the form of caricatures satirising or promoting the candidates, played a significant role.

Caricatures appeared almost daily, allowing the young artists Thomas Rowlandson and James Gillray both to make their names on the strength of their satirical output.