Northampton politics were dominated by two neighbouring families, the Montagus of Horton, earls of Halifax, and the Comptons of Castle Ashby, earls of Northampton. The corporation were an important factor from the power of the mayor and bailiffs as returning officers. In 1715 their patron was the Earl of Halifax, whose family held one seat in every Parliament from 1705 to 1734. The other seat was held by a Tory, William Wykes. In 1722 Wykes was ousted by William Wilmer, a Whig sponsored by Halifax, who rejected a Tory suggestion that he should ‘let his brother and Mr. Wykes be the two Members and ... dispose of Mr. Wilmer somewhere else’, saying that

if the county would have been content with one Whig and one Tory he would have been contented for one of each party for the town, but since there were to be two Tories for the county he hoped to have two Whigs for the town.

In 1727 Halifax came to an agreement with the new Earl of Northampton, under which their brothers were to share the representation of the borough. The object of the compact, ‘to hinder a contest’, was not achieved, for Wilmer stood, only to be overwhelmingly defeated by Montagu and Compton.

In 1734 the corporation transferred their allegiance to Lord Northampton, whose brother had voted against the ‘pernicious’ excise bill in accordance with their instructions, whereas Halifax’s brother had voted for it. At the election Compton, standing single, headed the poll, with Wilmer second, Montagu losing his seat. Montagu petitioned on the ground that the returning officers had acted illegally and partially in favour of Compton by making a great number of new freemen, who were not entitled to their freedom, and by permitting them to vote; but when the petition was heard at the bar of the House, his counsel took the line that freemen had usually voted at former elections, while Compton’s counsel relied on the last determination of the Commons that the right of election was in inhabitant householders only, whereupon Montagu’s counsel informed the House that if they were of that opinion he was not prepared to maintain a majority of votes for his client, leaving Compton to be declared duly elected.1

In 1741 Compton and Wilmer were unopposed but on Wilmer’s death in 1744 the Montagus recovered their seat. In 1747 the Earls of Halifax and Northampton revived the electoral pact of 1727. Shortly before the election Lord Northampton wrote to the corporation recommending Lord Halifax’s first cousin, George Montagu, who was duly returned unopposed with George Compton. In the 2nd Lord Egmont’s electoral survey, c.1749-50, Northampton is described as ‘in Lord Northampton and Lord Halifax’.