"Ash" joined Casualty at the beginning of series 5, as staff nurse. He was living with student girlfriend Nicki during series 7, but they split up after she got pregnant and had an abortion.
At the beginning of series 8, Kenneth Hodges got the job Ash had applied for, and he was jealous, but the post was abolished not long after. When Duffy left, Ash was promoted to charge nurse.
During series 9, after trouble at an anti-racist march, Ash was threatened and verbally abused by racists. On leaving the department at the end of the shift, he found himself face-to-face with Hitchins, one of the racists, holding a knife. Ash kicked him in self-defence, and the thug was hospitalised and Ash was charged with ABH. The only witness to the incident did not see the knife, and things looked bleak for Ash until Matt Hawley stepped onto the witness stand and said he'd heard Hitchins threaten to kill Ash. Ash was cleared of the charges, but felt uncomfortable on returning to work, and took up a teaching post for a few months.
Ash had returned by series 10, and started a relationship with Laura Milburn. After a few ons and offs, he proposed to her and they were married at the end of the series. Ash then left Holby, as Laura had to find a job elsewhere.
Ash returned to be best man at Charlie and Baz's wedding, and revealed that his marriage had collapsed and he was fighting for custody of their daughter Ella; he was giving up nursing to become a lawyer so he could have more control of his time.