The growth in super-fit 60-somethings is also down to greater awareness of the need to stay healthy as we get older, according to personal trainer and movement specialist Ashley Grossmann.

‘People are starting to realise that our sedentary lifestyles and inactivity are the cause of a lot of the problems associated with ageing,’ he says. ‘For example, there’s research to show osteoporosis is closely linked to inactivity, and in Australia there are physios who prescribe weightlifting to the elderly because it increases bone density and protects against breaks.’

Running enthusiast Chris Finill, a 60-year-old finance bursar at Duke of Kent Independent School, does marathons in his spare time. ‘I started running to and from work in the early 1980s, around the time of the first London Marathon, and back then you were really looked down upon for turning up at work in a muddy tracksuit or sweaty T-shirt,’ he says. ‘But these days it’s completely mainstream.’

Finill has done every London Marathon since the event began in 1981, and holds the world record for running it in sub-three hours for 33 consecutive years. This year he clocked in at two hours 59 minutes.

‘I think the reason why I’ve not slowed down much is because I never trained hard in my 20s,’ he reflects. ‘I didn’t flog myself to the point where I was badly affected by injuries in my middle age. And nowadays, looking back, I’m pleased, as runners who were far better than me at the same age are no longer running because they messed up their knees or lost their enthusiasm through doing it too much when they were younger.’

Training five times a week, Finill runs at least five or six miles on weekdays and 10 to 12 miles at weekends; more if he’s gearing up for a marathon.

‘It’s always quite satisfying to beat people who are less than half my age, but it’s more about me feeling good about my own performance and what I can achieve,’ he maintains. ‘Ageing is inevitable, but trying to be the best athlete in my 60s isn’t a lot different from trying to be the best in my 20s. It feels the same – it still hurts, and you still get that exhilaration when you run well.’

Finill plans to continue running ‘until I drop!’ and clearly his achievements are exceptional. But it’s no longer exceptional for someone of his age to run a marathon. The London Marathon has seen a steady rise in the number of finishers aged 60-plus every year for the past seven years, representing an increase of nearly 25 per cent since 2013.

We’re capable of much more than we give our bodies credit for, says Finill. ‘You have to ask it nicely, but the body is able to do an awful lot.’ This view is endorsed by Professor Stephen Harridge from the Centre for Human & Applied Physiological Sciences at King’s College London.

‘It’s true that our physical performance and capability declines as we age. We know this when we study master athletes – older people who are still competing in running, cycling, swimming and so on. Their performances decline over time, even though they’re still training very hard and doing all the right things. But despite knowing this, we still seem to set the bar quite low for the expectation of our physical activity levels,’ Harridge asserts.