There is a common misunderstanding about life expectancy, as though it is the age at which most adults could expect to die.
In fact, the mean length of life can be heavily skewed by infant mortality. For example, in 1850 in England and Wales life expectancy at birth was 42, but over 25% of children died before the age of five. For those who survived, life expectancy rose to 57. Moreover, 10% of people born in 1850 lived to over 80.
While we do not have detailed figures for the iron age (Hilda the iron age druid reconstructed in wax, 15 August), it would not be so unusual for someone with a life expectancy of 31 at birth, who then manages to survive the dangers of childhood, to live to 60 or later.
Mary Reid
Chessington, London
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