The “Special Order” Had Come From the Buckingham Palace Earlier
Prior to the ceremony, The Daily Mail had reported on Monday that a “special order” was delivered by the 96 years old queen to deliver the speech on her behalf. The order was delivered through what is called the Letters Patent. It was reported that the Letters Patent directly addressed the heirs of the monarch: The son, Prince Charles, and the grandson, Prince Williams.

E Online / Prince Charles and Prince Williams are the immediate heirs of the British monarchy. Reveals the Letters Patent.
Nevertheless, it is pertinent to mention that the 96 years old queen has been facing difficulty with mobility given her age and bodily fragility. The Daily Mail reported that the queen “faces trouble with outings.” In the absence of the queen, the two princes (Prince Charles and Williams) are the State Counsellors. And they are the only political figures who can carry on the parliamentary affairs – in the absence of the queen.