The Chatham ministry was a British government led by William Pitt, 1st Earl of Chatham that ruled between 1766 and 1768. Because of Pitt's former prominence before his title, it is sometimes referred to as the Pitt ministry. Unusually for a politician considered to be Prime Minister, Pitt was not First Lord of the Treasury during the administration, but instead held the post of Lord Privy Seal.
Pitt, who moved to the House of Lords as Earl of Chatham upon his accession to the ministry, was determined to form a ministry of "measures, not men" that would give office to the most competent men without regard to faction. Thus, the ministry kept on Secretary of State Henry Seymour Conway from the previous, Rockingham Whig, ministry, and, after Chatham's brother-in-law Lord Temple refused the Treasury and decided to continue in opposition with his brother, former prime minister George Grenville, he promoted Conway's fellow Rockingham Whig the Duke of Grafton to that position. Chatham's own close associates Lord Camden and Lord Shelburne became Lord Chancellor and Southern Secretary of State, respectively, and the ministry was filled out with other politicians of unclear factional allegiance – keeping on Lord Egmont at the Admiralty and Lord Granby at the Ordnance Board, moving the former Lord Chancellor, Lord Northington to the sinecure position of Lord President of the Council, and appointing the slippery Charles Townshend to the Exchequer.
Chatham was ill with gout for long periods, and his government struggled to fulfill its various goals. Almost immediately its "measures, not men" philosophy began to come apart when Lord Egmont resigned the Admiralty due to his opposition to Chatham's foreign policy and was replaced by the Rockingham Whig Sir Charles Saunders. Its major foreign policy objective – to secure Britain a major alliance partner in Europe that would end its diplomatic isolation – failed when Frederick the Great of Prussia rejected an offer to reform the Anglo-Prussian Alliance.
Soon after, Chatham managed to largely alienate the heretofore cautiously friendly Rockingham faction by dismissing their ally Lord Edgcumbe, the Treasurer of the Household. Though both Grafton, who had already been moving away from the Rockinghams due to his strong admiration for Pitt, and Conway remained in the ministry, Saunders and a large number of non-cabinet officeholders from the Rockingham faction resigned their positions. Though Saunders was replaced by the competent Admiral Sir Edward Hawke, most of the other positions were given to former supporters of the royal favourite Lord Bute, increasing the unpopularity of the ministry and strengthening the opposition. At around the same time, and with Chatham absent from the capital, the ministry was further riven by Chancellor Townshend's introduction of the idea of what was to become the Townshend Duties on the American colonies, which strongly divided the ministry.
In the midst of this crisis in early 1767 Chatham apparently had a nervous breakdown and withdrew entirely from the conduct of affairs. Grafton attempted to maintain the ministry in his absence, but with difficulty due to the alliance between the three opposition factions of the Rockingham Whigs, Bedford Whigs, and Grenvillites and to conflicts within the ministry itself. After an unsuccessful attempt to bring his former allies in the Rockingham faction to support the government, Grafton instead turned to the Bedfords, leading to a major reconstruction of the ministry in late 1767 and early 1768, with Bedford's followers Lord Gower and Lord Weymouth as Lord President and Northern Secretary (Conway became a minister without portfolio), and the like-minded Lord Hillsborough given the new office of Secretary of State for the Colonies – taking responsibility for the American colonies from the more conciliatory Shelburne, whose differences with the rest of the cabinet had led him to cease attendance at cabinet meetings. The death of Charles Townshend had also led to his replacement at the Exchequer by Lord North, who also took leadership of the commons over from Conway, who was increasingly uncomfortable with the direction of the ministry.
The adhesion of the Bedfords ultimate gave them a dominant role in the ministry, which they used to pursue a more hardline policy towards the American colonies than Chatham had originally intended, or than several of the remaining were comfortable with. In October 1768, the Bedfords persuaded Grafton that it would be necessary to remove Shelburne from the ministry. This threatened dismissal roused Chatham, who resigned his post alongside Shelburne. Although Chatham's close friend Camden remained in the government, it was clear that the ministry was now dominated by the Bedfords, and the Duke of Grafton formally took over as Prime Minister and led the Grafton ministry, which lasted for slightly over a year until January 1770.
|Portfolio||Minister||Took office||Left office||Party|
|First Lord of the Treasury||The Duke of Grafton||30 July 1766||14 October 1768||Whig|
|Lord Chancellor||The Lord Camden||30 July 1766||14 October 1768||Whig|
|Lord President of the Council||The Earl of Northington||30 July 1766||22 December 1767||Whig|
|The Earl Gower||22 December 1767||14 October 1768||Tory|
|Lord Privy Seal||Earl of Chatham*||30 July 1766||14 October 1768||Whig|
|Chancellor of the Exchequer||Charles Townshend||30 July 1766||4 September 1767||Whig|
|Lord North||4 September 1767||14 October 1768||Tory|
|Henry Seymour Conway||30 July 1766||20 January 1768||Whig|
|The Viscount Weymouth||20 January 1768||14 October 1768||Tory|
|Secretary of State for the Southern Department||The Earl of Shelburne||30 July 1766||14 October 1768||Whig|
|Secretary of State for the Colonies||The Earl of Hillsborough||27 February 1768||14 October 1768||Independent|
|First Lord of the Admiralty||The Earl of Egmont||30 July 1766||September 1766||Tory|
|Sir Charles Saunders||September 1766||December 1766||Independent|
|Sir Edward Hawke||December 1766||14 October 1768||Independent|
|Master-General of the Ordnance||The Marquess of Granby||30 July 1766||14 October 1768||Whig|
|Minister without Portfolio||Henry Seymour Conway||30 July 1766||14 October 1768||Whig|
First Rockingham ministry
| Government of Great Britain