King Charles 'frustrated' by cancer diagnosis for key reason that's left him 'a caged lion'
![King Charles 'frustrated' by cancer diagnosis for key reason that's left him 'a caged lion'](https://i2-prod.mirror.co.uk/incoming/article32737934.ece/ALTERNATES/s615/1_Royal-Windsor-Horse-Show-Day-3.jpg)
King Charles is one of the nation's most-prolific letter writers and his pen pals have revealed that his correspondence remain "full of light" despite his health having been "somewhat battered"