(Oralndo Seale)
Merlin started work as PRHO in A&E during series 17. He had started seeing Anna Paul shortly before starting work there.
Merlin had been adopted at birth, and had never been curious about his birth mother until one of his patients, who had also been adopted, suddenly discovered she had a serious condition, inherited from her natural parents. Merlin decided to contact his birth mother and eventually arranged a meeting, but was disappointed when she didn't turn up. It was Anna who discovered that Merlin's birth mother was her own mother...