1759-1806. William followed in the footsteps of his father Pitt the Elder, Earl of Chatham, and was a talented speaker. The youngest Prime Minister in British history, he was aged 24 upon taking office and served as Prime Minister for a total of nearly 19 years. He was a Tory in his views but in the ambiguous politics of the time regarded himself as an independent Whig. He had a reputation as a heavy drinker and was prescribed a bottle of port a day for his gout by Dr Anthony Addington, father of Pitt's successor as Prime Minister.

• 1759: Born on 28 May at Hayes, Kent, the fourth of 5 children
• Educated at home due to poor health and then at Pembroke Hall, Cambridge, graduating in 1776
• 1780: Called to the Bar 
• 1780: Unsuccessful parliamentary seat of Cambridge University in 
• 1781: Entered Parliament on 8 January as MP for Appleby (Westmoreland)
• 1781: Maiden Speech on 26 February on Edmund Burke's motion for the reintroduction of the Bill for Economical Reform
• 1782: Aged 22, he refused the post of Vice-Treasurer of Ireland in Rockingham's government as too subordinate for his talents
• 1782: Chancellor of the Exchequer and Leader of the House in Lord Shelburne's government
• 1783: Refused the King's invitation to form a government, but accepted after the Duke of Portland's administration collapsed. 
• 1784: Secured a very large majority in the General Election
• 1801: Resigns as Prime Minister. His successor, Addington wished to appoint Pitt as Chancellor of the Exchequer but Pitt insisted he would only return as Prime Minister in his own right.
• 1804-06: Prime Minister for a second time
• 1806: Died on 23 January at Putney Heath, London.

The First Administration (1783-1801)

Nugent Buckingham, a cousin of Pitt, was instrumental in bringing him to power. Fox had formed a coalition with North and promoted an India Bill. On 11 December 1783, Buckingham told the House of Lords, on the authority of the King, that 'whoever voted for the India Bill were not only not his friends, but he should consider them his enemies.' The Lords threw out the Bill and the King dismissed the coalition. Although Pitt appointed Buckingham Home Secretary, Buckingham resigned after just 4 days following a dispute with Pitt.  

A bitter rival to Edward Fox, Pitt championed a number of modernising causes, not always successfully:

• Parliamentary reform. He aimed to reduce the direct influence of the monarch and the potential for bribery. In 1785, however, Pitts Reform Bill to rationalise the "rotten borough" constituencies was rejected.
• Union with Ireland. Pitt's 1785 Union with Ireland Bill was rejected but his 1800 Bill uniting the Parliaments of England and Ireland was successful.
• Catholic emancipation. The 1793 Relief Act gave Catholics the right to vote in elections but not to sit in Parliament.
• East India Company. The 1784 India Act reorganised the East India Company and established dual control of it. 
• Reduction of the national debt. Pitt established a sinking fund; though this proved unsuccessful due to the Napoleonic Wars. 
• Smuggling. A reduction in customs duties and increased policing led to a fall in smuggling.
• Free trade. His proposals for free trade with Ireland and liberal trading with the United States failed.

In 1788, the King's mental illness led Pitt's opponents to advocate that sovereignty pass to the Prince of Wales. This developed into the Regency Crisis of 1789, with the Regent's cause championed by Fox. However, the King recovered, ending the crisis. 

Worries about the potential for revolution in England led Pitt to crack down on parliamentary reformers. Many prominent figures were imprisoned. Pitt's reputation as a reformer was further weakened by his refusal in 1788-91 to agree repeal of the Test and Corporation Acts to allow Dissenters to hold public office. Fox supported repeal as he did the French Revolution.

The War with France led to increased taxes and duties (see below), increasing Pitt's unpopularity and making it necessary for Pitt to be given armed protection. Press speculation about his mental health at this time angered him so much that he suppressed the newspapers. He suspended habeas corpus in 1794.

In 1800, Pitt's Act of Union with Ireland aimed to resolve the conflicts there and grant Catholics equality. However, in 1801 the King refused to accept Pitt's Emancipation of Catholics Bill, claiming that assent would break his coronation oath of loyalty to the Church of England. As a consequence, Pitt resigned, having lost the confidence of the King.

The War With France

In 1791, Pitt declared Britain to be neutral towards the revolution in France but changed his stance in 1793. As a result, Pitt was blamed by Fox for taking Britain into war with France:

• 1789: Beginning of the French Revolution
• 1792: Pitt declared that there will be 15 years of peace in Europe
• 1793: Pitt expelled the French Ambassador on hearing that King Louis XVI had been executed in January
• 1793: France declared war on Britain
• 1793: On 1 February, Pitt decided to form a broad European coalition against France; between March and October he concluded alliances with Russia, Prussia, Austria, Spain, Portugal and some German princes
• 1794: Taxation increased to raise a loan of £18 million to pay for the war against the French at a time when basic foods were scarce
• 1794: British troops pull out of the Netherlands, which fell to France
• 1794: The Suspension of Habeas Corpus Act was passed on 7 May and habeas corpus was suspended from 16 May 1794 until July 1795.
• 1795: When travelling to open parliament in October, George III is greeted with cries of 'Bread', 'Peace' and 'no Pitt'
• 1796: In October, Spain enters the war in support of the French 
• 1797: Worsening finances, force Britain off gold standard 
• 1797: Austrians make peace with France
• 1798: Nelson successfully destroys Napoleon's fleet at the Battle of the Nile
• 1798: French stir up rebellion in Ireland
• 1798: Habeas corpus again suspended from April 1798 to March 1801
• 1799: Napoleon Bonaparte's offer of peace to Britain is rejected 
• 1799: Pitt introduced a new graduated income tax; beginning with less than 1% on incomes of £60 and rising to 10% on incomes of over £200
• 1802: Treaty of Amiens gave a temporary peace with France under Henry Addington's government.

The War led to many of Pitt's intended reforms being postponed indefinitely. 

The Second Administration (1804-06)

In 1804, Napoleon was threatening invasion and the King asked Pitt to form his second government. Pitt was in failing health, an alcoholic and commanded limited support in the Commons. Nevertheless, he agreed. He wished to bring Fox into his coalition as Foreign Secretary but this was vetoed by the King. As a result the Foxites and the Grenvillites refused to join his administration. 

Pitt formed an alliance with Russia, Austria and Sweden to fight the French. He was hailed as a saviour following Nelson's victory at the Battle of Trafalgar. However, Napoleon went on to conquer Europe by defeating the Russian and Austrian armies in 1806, a major blow for Pitt.

William Pitt the Younger died at the age of 46 on 23 January 1806. He was unmarried and in debt, having given his entire life to politics.