At 68, Clare Roden is one of more than 8,000 doctors in the NHS working beyond retirement age. The additional income is low on her list of reasons to keep going.

Dr Roden, a GP since 1971, says she found the work so engaging that she did not want to stop at 60, when she would have been eligible to retire. "I did it for 30 years and was sorry to leave it," she says.

She officially retired at 65, but within six weeks her surgery in Greenwich had asked her back for one and a half days a week. "It was just like slotting back in after a long holiday," she says. Many doctors make the same choice when they hit retirement age.

Part of the area the practice serves is in Woolwich, home to some of the UK's most deprived residents, where drug abuse and chronic unemployment underlie healthcare needs.

"I still find it stimulating. It is something different every single day and you never cease to marvel at human behaviour," Dr Roden says. She plans to keep working until she is 70.

Many of her older patients work. They see work, she says, partly as combatting the social isolation that all too often goes with old age.

Witnessing the best and the worst of human behaviour has scarcely dulled Dr Roden's appetite for work.

For many years she was a police surgeon, charged with a range of tasks from determining the fitness of suspects for questioning to examining rape and child abuse victims.

When she is not working she looks after her grandchildren, attends art history classes and frequents the opera. "Your 60s are the best time of your life," she says.