King Charles "cuts bits of [his] fingers off" while gardening

Speaking to presenter Martha Kearney on BBC Radio 4's This Natural Life programme for a Christmas special, he said: "[I spent] my life going around with my secateurs. I do cut bits of my fingers off occasionally."

The king credited his passion for the natural world to his childhood memories with his great-great-grandmother.

He said: "I have some very extraordinary memories of...Queen Alexandra's wonderful little topiary garden at Sandringham.

"That really fascinated me as a very small child, and I've had this passion for topiary ever since. Extraordinary."

And the king remembered his own grandmother's garden, where she used to encourage him to "potter about" and discover plants.

He said: "So I became more and more aware [of the natural world], but I think I was just one of those people who responded to being outside and looking and observing.

"That's where grandmothers come to say, 'Look at this'".

But Charles - who has sons Princes William and Harry with late ex-wife Princess Diana - admitted he has failed to pass his enthusiasm on to his own grandchildren.

He said: "I try but it doesn't always work."

The staunch environmentalists believes children should be encouraged to grow fruit and vegetables at school.

He said: "This is always the challenge, isn't it? I think half the battle is trying to find a way to enable more children to help with school vegetable gardens."

The royal believes doing so would give children a sense of attachment to what they were growing, which would hopefully spark them to "start thinking about the effects of climate change on those vegetables or fruit".

Lamenting the closure and sell off of many school farms, he added: "They were marvellous ways for people to learn biology or economics, or goodness knows what else, because [it included] actually looking after animals as well."

The king has "tried to demonstrate" alternative ways to improve the environment through his various initiatives over the world and believes people should "always [be] putting something back into nature in return for what we take out".

He added: "So nature should have a bit of the profit, if you see what I mean. Otherwise, how are we going to survive with our own economy if we don't look after nature's economy?"