A list of Records of Prime Ministers of the United Kingdom.

Period of Service

The Prime Minister with the longest single term was Sir Robert Walpole, lasting 20 years and 314 days from April 4 1721 until February 11 1742. This is also longer than the accumulated terms of any of other Prime Minister.

George Canning, who served the shortest total period as Prime Minister (1827).

The shortest period in office is more confused, depending on the criteria.

In November 1834, Arthur Wellesley, 1st Duke of Wellington declined to become Prime Minister in favour of Sir Robert Peel but formed a "caretaker" administration for 25 days (November 17 1834-December 9 1834) whilst Peel returned from Europe. However as a caretaker administration this is not considered a term of office in its own right.

Of those with clear terms, the Prime Minister with the shortest single one was Charles Watson-Wentworth, 2nd Marquess of Rockingham, whose second term last 87 days from March 27 1782 until his death on July 1 1782. However combined with his first term (July 13 1765-July 30 1766) his total time in office was 1 year and 113 days which exceeds the total periods of several other Prime Ministers.

The Prime Minister with the total shortest period in office was George Canning, whose sole term lasted 119 days from April 10 1827 until his death on August 8 1827.

Other notables

The Prime Minister with the longest period between the start of their first appointment and the end of their final term was William Cavendish-Bentinck, 3rd Duke of Portland, whose first term began on April 2 1783 and his second and final term ended on October 4 1809.

Portland also holds the record for the longest period between terms - his first term ended on December 19 1783 and his second term did not start until March 31 1807.

Number of terms

A Prime Minister's "term" is traditionally regarded as the period between their appointment and dismissal, with the number of general elections taking place in the intervening period making no difference.

The only Prime Minister to serve four terms was William Ewart Gladstone (December 3 1868-February 20 1874, April 23 1880-June 23 1885, February 1 1886-July 25 1886 & August 15 1892-March 5 1894).

Age at appointment

The youngest Prime Minister to be appointed was William Pitt the Younger on December 19 1783 at the age of 24 years, 6 months and 21 days.

The oldest Prime Minister to be appointed for the first time was Henry John Temple, 3rd Viscount Palmerston on February 6 1855 at the age of 70 years 3 months and 17 days.

The oldest Prime Minister to be appointed of all was William Ewart Gladstone, who was born on December 29 1809 and appointed for the final time on August 15 1892 at the age of 84 years, 7 months and 3 days.

Longest Lived

The longest lived Prime Minister was James Callaghan, who was born on March 27 1912 and who died on March 26 2005 at the age of 92 years, 11 months and 30 days. Prior to this the longest living Prime Minister was Harold Macmillan who was born on February 10 1894 and died on December 29 1986.

Of the former Prime Ministers currently alive, the oldest is Edward Heath who was born on July 9 1916.

Shortest Lived

The shortest lived Prime Minister was William Cavendish, 4th Duke of Devonshire who was born in 1720 and died on October 2 1764 at the age of 44 years.

None of the Prime Ministers currently alive is younger than this.

Longest Lived after office

The Prime Minister who lived the longest after leaving office for the final time was Augustus FitzRoy, 3rd Duke of Grafton who left office on January 28 1770 and died on March 14 1811, a total of 41 years, 1 month and 17 days.

Henry Campbell-Bannerman, who lived the shortest after leaving office.

Of the former Prime Ministers currently alive the earliest to leave office was Edward Heath whose term ended on March 4 1974, more than 31 years ago.

Shortest Lived after office

The Prime Minister who lived the shortest period after leaving office (excluding those who died in office) was Sir Henry Campbell-Bannerman who resigned on April 3 1908 and died 19 days later.

Only Assassinated Prime Minister

The only Prime Minister to date to have been assassinated was Spencer Perceval, who was shot by John Bellingham on May 11 1812.