Lord Grenville retired from active politics in 1817, leaving Grey as the leader of the opposition in the House of Lords. Grey was not a former prime minister in 1817, unlike Grenville, so under the convention that developed later in the century he would have been in theory of equal status to whoever was leader in the other House. However, there was little doubt that if a Whig ministry was possible, Grey rather than the less distinguished Commons leaders would have been invited to form that government. In this respect Grey's position was like that of the Earl of Derby in the Protectionist Conservative opposition of the late 1840s and early 1850s.