Britain's Prince Harry may no longer be an active rugby player but the former schoolboy scrum-half has said he was still like a "Labrador with a tennis ball" whenever he sees a rugby ball.

Harry, the younger son of Prince Charles, is the patron of England's Rugby Football Union and made his remarks Friday as he visited their Twickenham headquarters ground in southwest London to celebrate grassroots clubs and charities using rugby for good.

The prince also saw the senior England men's team put through their paces ahead of the Six Nations champions' next match, away to Scotland, a week on Saturday.

Before stepping onto the pitch to watch England train in front of an invited audience of some 10,000 people, he spoke to representatives of organisations that have received grants from the RFU's "Try For Change Fund".

Harry and England's 2203 Rugby World Cup-winning drop-goal hero Jonny Wilkinson spoke to teenagers supported by the Plymouth Sports Charity who have been working towards becoming rugby coaches as a way of encouraging their personal development.

Asked about his own rugby history, Harry said: "I played for years, I played scrum-half for about five or six years until I got too tall and instead of being a forward I elected to be a fly-half."

He added he no longer played after "numerous injuries", before insisting "but I'm like a Labrador with a tennis ball as soon as I see a rugby ball".

The prince also told the young coaches: "Honestly, it's guys like you... you're now the ambassadors for the sport and the difference it makes.

"We can spend as much time as we can trying to drill it into people but you're it and the fact it works and makes a difference and is so simple -- the most important thing is that development and you are having fun at the same time."