In the last week of September 1756, Sir James Lowther of Lowther, the famous eighteenth-century boroughmonger, spent more than 58,000 pounds securing 134 burgages in the parliamentary borough of Cockermouth. When added to the twenty-four he already possessed this gave him more than half the total. As a result, he was recognized thereafter as being able to return both members for the borough. The Earl of Egremont, whose family had held the strongest interest since the borough was restored in 1641 to the ancient privilege of returning two members to parliament, was completely eclipsed. His younger brother, Percy Wyndham O'Brien, who had been returned with his support in 1754, retreated to Minehead at the 1761 election. Cockermouth was not contested again before the 1832 Reform Act, and its two members were counted among Lowther's famous ninepins.
Pocket boroughs were one result of the oligarchic structure that came to characterize English political life by the middle of the eighteenth century. The vigorous party struggles of Queen Anne's reign had melted away following the eclipse of the Tories and the passing in 1716 of the Septennial Act. In its place came the long Whig ascendancy, a period of political torpor that rendered burgage boroughs, in the words of Sir Lewis Namier, “predestined to become pocket boroughs.” Longer parliaments pushed up the cost of election contests, which in consequence became less frequent. If one did take place and the result was close, the inflated cost of canvassing was likely to be compounded by the near certainty of a petition.