A Treasury spokesman said the bulk of people who will be affected would currently be in their mid to late 40s.

  One thing is certain, though: the revised policy will save an awful lot of money.

  "The figures previously published show that delaying the state pension age by one year saves the government £13bn," said Malcolm McLean, a consultant at the actuaries Barnett Waddingham.

  "Further rises in the state pension age and linking it to life expectancy are not unexpected given that people continue to live longer and therefore the cost of providing a state pension will inevitably increase."

  Indeed, the Autumn Statement says the latest rise in the state pension age, along with the other scheduled increases, might eventually save taxpayers about £500bn over the next 50 years.