"It is for me a great sadness that I cannot be with you all today," the monarch said.
"In this country we are blessed by all the different services that exist for our welfare, but over and above these organisations and their selfless staff we need and benefit greatly from those who extend the hand of friendship to us, especially in a time of need."
The recording was made before his daughter-in-law, Kate, the Princess of Wales and wife of his eldest son Prince William, issued a video message in which she revealed she was having preventative chemotherapy after cancer was discovered in the aftermath of abdominal surgery in January.
