The Queen prepared Prince William to be King with careful mentoring and weekly tea and cakes from childhood

ok.co.uk:

After Prince William had started as a boarder at Eton College in 1995, he would disappear for several hours every Sunday. When fellow pupils asked where he was going, 13-year-old William would reply, “I’m just off to the WC.” He was actually going to visit his granny at neighbouring Windsor Castle.

However, a modest William didn’t like to remind his friends he was their future king.Those low-key visits to the Queen became a cherished ritual for the prince, and helped forge a strong bond between monarch and heir presumptive.The link she would later develop with William’s wife, KateMiddleton, would also play a crucial part in the future of the House of Windsor. “The Queen plays a very special dual role in William’s life,” says Katie Nicholl,.