Boris Johnson will become prime minister at an age older than many of his immediate Tory predecessors, including David Cameron and John Major.
Mr Johnson is currently 55, making him 12 years older than Mr Cameron (43) when he became PM in 2010.
John Major was 47 – eight years younger than Johnson – when he became PM in 1990.
Mr Johnson also outranks two other recent Conservative prime ministers: Margaret Thatcher and Edward Heath.
Mrs Thatcher was 53 – two years younger than Johnson – when she took office in 1979.
Edward Heath was also 53 when he took up the role in 1970.
Johnson’s immediate predecessor Theresa May became prime minister at a slightly older age, however.
She was 59 when she took office in 2016.
Johnson and May are within an age bracket that has more in common with Conservative prime ministers of the 1950s and early 1960s than those from more recent decades.
Anthony Eden was 57 on becoming PM in 1955, Alec Douglas-Home was 60 in 1963, while Harold Macmillan was 62 in 1957.