Justice Secretary Ken Clarke says the state pension age will rise to "the late 60s" as the current system is "unaffordable".
Clarke said chancellor George Osborne and secretary of state for work and pensions Iain Duncan Smith are still "locked in discussions" over the pension age, BBC Radio 4's World at One programme reports.
"A universal retirement benefit at the age we had, it was unaffordable," Clarke said.
"Think of our children, think of our grandchildren, who are going to have to pay for it when there are many fewer of them than there are these long-lived retired people we have now."
The coalition government has suggested raising the state pension age to 66 for men from 2016, rather than by 2024 as the Labour government planned to.
Clarke went on to criticize French attitudes to the pension age: "The French have been so mad as to have riots in the street raising their age from 60 to 62 when our age is about in line with the normal, when you will find across Europe I think the retirement age will drift up into the late 60s."
France faced its third 24 hour strike on Monday as President Nicolas Sarkozy pushes to raise the retirement age.
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