Alice Marples, 10, who has received treatment at the Royal Marsden Hospital in London since she was four years old, asked him what he would have done if he was not a prince.

He replied: "A long time ago, I wanted to be a policeman. I soon learned that was probably not a good idea."

In the interview for CBBC's Newsround programme, he also spoke about his charity work and how he got his 'Harry Potter' scar.

He said that he was following in his mother's footsteps by lending his support to plans for a new children's and teenage cancer centre at the hospital.

The prince, now 26 years old, told Alice: "At the moment I'm still doing some sort of helicopter flying, doing search and rescue. It's going very well."