Prince Andrew described Philip as a "remarkable man" after he left a private service in Windsor, where his father died on Friday at the age of 99.
"It's a great loss," he said. "I think the way I would put it is we've lost almost the grandfather of the nation."
He said the family was rallying around his 94-year-old mother, adding she was stoical in the face of a loss that she had described as "having left a huge void in her life".
Andrew has rarely been seen in public since he stepped down from official duties in 2019 over the controversy surrounding his association with the disgraced late U.S. financier Jeffrey Epstein.
The Queen's youngest child Prince Edward, his wife and their daughter also attended the private service.