List of British Prime Ministers Who Are Related to Each Other

The first modern British Prime Minister is generally acknowledged to be Sir Robert Walpole, who was Prime Minister from April 1721 to February 1742. Therefore there has been a series of prime ministers for nearly 300 years. However despite Britain's intensely class-driven society, there seems to be a distaste for hereditary politics - very few modern British prime ministers have been related to each other, and when there is a relation, it is distant and sometimes the individuals were not aware of it.

This page traces those Prime Ministers who have a family relation.

1. William Pitt the Elder, George Grenville and William Pitt the Younger. William Pitt the Elder, 1st Earl of Chatham, was Prime Minister from July 1766 to October 1768. His son William Pitt the Younger was Prime Minister from December 1783 to March 1801, and again from May 1804 to January 1806. They represented different political parties - the Elder was a Whig and the Younger was a Tory. There was consternation when William Pitt the Younger became Prime Minister, but not because of his relationship with his father, but because he was so young. He was just 24 when he became Prime Minister - people exclaimed that it was “a sight to make all nations stand and stare: a kingdom trusted to a schoolboy's care”.

William Pitt the Younger's mother was the sister of George Grenville, a Whig who was Prime Minister from April 1763 to July 1765. William Pitt the Younger's achievements eclipsed that of both George Grenville and William Pitt the Elder - among his achievements was the introduction of income tax.

2. William Grenville, George Grenville and William Pitt the Younger. William Grenville, 1st Baron Grenville was Prime Minister from February 1806 to March 1807. He was the son of George Grenville, Prime Minister, and first cousin of William Pitt the Younger. William Grenville was a Whig and his main achievement was the abolition of the slave trade.

3. Robert Gascoyne-Cecil and Arthur Balfour. Robert Gascoyne-Cecil, 3rd Marquess of Salisbury was Prime Minister from July 1886 to August 1892, and then from June 1895 to July 1902, and Arthur Balfour was Prime Minister from July 1902 to December 1905. Both were Conservatives. Arthur Balfour's mother was the niece of Robert Gascoyne-Cecil. Both Gascoyne-Cecil and Balfour are descended from William Cecil, 1st Baron Burghley, who was the powerful chief advisor to Elizabeth I, and his son Robert Cecil, 1st Earl of Salisbury, who was chief advisor to James I.

This means that the Cecil family were effectively prime movers in the pre-modern system, as well as in the post 1721 system, having contributed four people who were effectively Prime Ministers.

4. Margaret Thatcher and John Major. Margaret Thatcher was Prime minister from May 1979 to November 1990 and she was succeeded by John Major who was Prime Minister from November 1990 to May 1997. Margaret Thatcher was from a lower middle-class family and John Major was from a working class family, so it came as a surprise to both when genealogists discovered, after they had left office, that they were related.

They are both descended from John and Elizabeth Crust who were tenant farmers in Lincolnshire in the 18th Century. This makes the two Prime Ministers fifth cousins.

Thatcher and Major presided over a turbulent period of economic reform, but in legislative terms their most important work related to the European Union. Thatcher negotiated and signed (and by some accounts significantly authored) the Single European Act, which replaced the old EEC and created the EU, with free movement of goods and people for the first time. John Major signed the Maastricht Treaty which set up the euro (though he negotiated an opt-out for Britain).


As you can see, the only period of consciously hereditary politics took place in the 18th century with the Pitt and Grenville families and then there was a revival of the Cecil family in the late 19th century and start of the 20th. After that you got a series of unrelated Prime Ministers till we come to Thatcher and Major, who were unaware of their family connection.

Related article:

Seeking the Lost Kings of England

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