The Duke of Cambridge has spoken about his “passion” for farming and revealed that his children are already playing on tractors as he prepares to one day inherit the Duchy of Cornwall from his father.

William appears in a two-part documentary series commissioned by ITV to mark the Prince of Wales’s 50th working year as the Duke of Cornwall.

The second episode, airing at 9pm on Thursday October 31, offers a behind-the-scenes glimpse into the Duchy of Cornwall, which covers more than 130,000 acres across 23 counties.

The Prince of Wales interviewed in the Duchy of Cornwall documentary
The Prince of Wales is marking is 50th working year as the Duke of Cornwall (Prince Charles: Inside The Duchy Of Cornwall/PA)

It shows William meeting farmers as he prepares to take over running the estate when his father accedes to the throne.

During a visit to a Duchy farm, William said he should have brought along his eldest child, Prince George.

“He would be absolutely loving this. He’s obsessed,” William said with a laugh.

William speaks to farmers about how vital family is to the estate and how important the outdoors are to his own family.

“My children are already playing on the tractors and … it’s so important to get outside, and have the children understand nature,” William said.

Charles’s eldest son said he is “very passionate” about farming and is learning as much as he can on the Queen’s estate at Sandringham.

“I am very passionate about my farming and I just want to learn more about it,” he said.

As William prepares for his future role, he asks farmer Mervyn Keeling if there is anything the Duchy could be doing better for its tenants.

Mr Keeling explains Brexit is a big rural issue.

“We had a meeting with your father, he arranged it about Brexit … but even they couldn’t answer the questions for us,” Mr Keeling said.

“Because nobody knows, but it was nice, ‘cos I spoke to him afterwards, and your dad said he knows, and he was interested … he wants to make sure it’s right for us and for the countryside.”

In the documentary, Charles admits he is “touched” that William has taken an interest in the Duchy.

“When I saw it, I couldn’t believe it, I was deeply touched and moved by what he said,” Charles said.

“It practically reduced me to tears.

“Because I suddenly thought, well, just hearing that from him, has made the last 50 years worthwhile.”

The Duchy estate was established by Edward III to provide a private income for his son and heir to the throne Edward, later known as the Black Prince, and its purpose remains the same today.

Charles took over management of the Duchy when he was 21, after the Queen’s accession to the throne.

Today the estate is a private portfolio of land, financial investments and property including the Oval cricket ground in Kennington, south London, and 67,000 acres of Dartmoor.