Ms McMillan grew up in East Lothian and attended Ross High School in Tranent. She started her accountancy career with Ersnt & Young in London as a personal tax adviser before joining Chiene + Tait (which later rebranded as CT) in 1992.

Over the next three decades, she became an integral part of the firm as a director of its personal and business tax team. Ms McMillan worked with a wide range of clients across the UK, where she established herself as a leading specialist adviser in family and rural estate tax matters.

Highly regarded for her intelligence, pragmatism, kindness and great sense of humour, Ms McMillan developed close working relationships with clients and colleagues, with many benefitting from the years of mentoring and advice that she was always happy to share.

CT senior partner Jeremey Chittleburgh, who worked with Ms McMillan throughout her time at CT, said: “It is with great sadness that we share the news of Moira’s sudden passing. Our thoughts and deepest sympathies go out to her partner Susan and wider family at this difficult time.

“For over three decades, Moira was part of the CT fabric where her impact on colleagues and clients alike was immeasurable. Her warmth, intelligence, dedication, and the sheer joy she brought to every interaction will be deeply missed.”

Michelle Fallon, a CT personal tax partner and close associate of Ms McMillan, said: “We are all shocked and saddened by Moira’s sudden passing.

“She was much more than a colleague to myself and the team at CT who considered her a dear friend, mentor and role model. She was a wonderful person to know and to work with. We will treasure the time we spent with her.”