Nicky Gumbel writes: ‘Prince Charles has many tiles. He is the Heir Apparent to the Crown, his Royal Highness, the Prince of Wales, Duke of Cornwall, Knight of the Garter, Colonel in Chief of the Royal Regiment of Wales, Duke of Rothesay, Knight of the Thistle, Read Admiral, Great Master of the Order of Bath, Earl of Chester, Earl of Carrick, Baron of Renfrew, Lord of the Isles and Great Steward of Scotland. We would address him as ‘Your Royal Highness’, but I suspect to William and Harry he is known as ‘Dad’. When we become children of God, we have an intimacy with our heavenly King.

Source: The Official Website of The British Monarchy: ‘Style and titles’, https://www.princeofwales.gov.uk/titles-and-heraldry quoted by Nicky Gumbel, Alpha Questions of Life, 2007 edition, Eastbourne: Kingsway Communications, p.130-131