A survey of 1000 men and women over-50, found that the average Briton thinks that they are youthful until the age of 55 and old age does not set in until around 70, suggesting that middle age is the 14 years in between.
[Related: 10 surprising things that age you]
Celebrities such as Stephen Fry, 55; TV presenter and gardener, Alan Titchmarsh, 63; model Jerry Hall, 56; and Oscar-winning actress Helen Mirren, 67 were seen to be typical examples of the new "middle-agers."
The research, commissioned by Love to Learn, questioned the 50-somethings about their attitudes to life, ageing and what, if any, were the benefits of being older today in 2102 Britain.
According to the research, middle age was perceived to start at 55, and what's more, end at 69. But nearly one in five of those questioned said they thought middle age did not begin until after the age of 60.
Previous research concluded that middle age begins at 36, and that adults were considered "old" by the age of 58.
The findings suggest that, as the population is aging, new cut-off points are being drawn.
For the first time, more adults in the UK are aged over 45 than under 45 and more people aged over 65 than are under 16, according to Office for National Statistics data.
Gill Jackson, director of Love to Learn, which provides online courses for adults, said that people in their 50s were "overwhelmingly upbeat" about the benefits of their age group.
She said: "These new middle-agers are active, want to enjoy life and certainly don’t see themselves as 'old age pensioners!'
"They have greater freedom and financial security. More than half said they have more confidence and experience than younger people and are less afraid of making mistakes and a vast majority have a huge appetite to learn new things and take up new hobbies.”
Nearly nine out of ten (87%) of those surveyed said that pursuing new skills and hobbies such as learning how to use the internet helped them to keep their brain active. More than 40 per cent of grandparents said this had helped them to help their children and grandchildren.
TV presenter John Craven, who is helping to launch the website added: "Only a generation ago, many people were pretty old at 60.
"These days, most of us in our middle and later years are much younger in our attitudes and it’s all about having an active state of mind and the confidence to experience new things."