“It’s been such a privilege to be instructed on a landmark case like this so early in my career and to work with such an amazing team led by Sindi and Aidan O’Neill KC,” she says. “I’ve been involved with the case for the three years I’ve been at the firm, but it has a history that’s longer than that. It’s been a roller coaster in some ways – a huge amount of hard work goes into a case like this – but it’s a really exciting and complex area of the law. It really has been an amazing experience to work in such an experienced team and it was surreal to be in the Supreme Court so soon.”

Though her mother’s parents are Scottish and her father’s side of the family come from England, she was born and raised in Zimbabwe, which she describes as “a beautiful country with amazing friendly people and a lovely sunny climate”. She moved to the UK in 2014 to study law and history at the University of Glasgow, in part so she could feel connected to her family heritage. The move was, she says, initially a culture shock, but she enjoyed the variety of the joint honours course and threw herself into university life as part of the sailing club. With her younger brother also moving to Scotland to study, when her course finished she decided to stay.

“I trained at Balfour & Manson but I took a bit of a bit of time to get there,” she says. “I graduated in 2018 and worked as a legal analyst at Ashurst. The work I was doing was quite different – the legal analyst team is part of their new-law division and was focused on efficiencies and specifically the efficient use of technology. I was exposed to legal tech and legal project management. It was a really young international team and it was good to be exposed to working full time in a modern, progressive law firm.

“At that time, I wasn’t completely decided on whether I would qualify as a solicitor. I did a masters in European and international human rights law in the Netherlands then when I came back in 2021 I started the diploma. I joined Balfour & Manson then qualified last year.”

Ms McCosh says that, as a student, she had always thought of Balfour & Manson as a “prestigious public law firm” and she found the traineeship there “very fast paced”.

“I got thrown in a bit,” she continues. “I was very well supported, but from day one I was contributing to cases. What was so exciting in the public law team was that those cases were high-profile, challenging and really fascinating. The team works in a very collaborative way and my opinion was sought from a very early stage.”

The first-ever matter she worked on as a trainee was a Court of Session case brought by housing charity Shelter Scotland against City of Edinburgh Council. Then she quickly moved on to Glasgow Sheriff Court to argue a religious discrimination case against the Scottish Event Campus, which is majority owned by Glasgow City Council, on behalf of the Billy Graham Evangelistic Association. In that matter Sheriff John McCormick ruled that the council had put pressure on the campus to cancel a showcase event from the evangelist Franklin Graham – son of the late Billy Graham – but that doing so had been in breach of the Equality Act. McCosh was also involved in the Kaagobot case, which saw Court of Session judge Lord Richardson overturn a decision by City of Edinburgh Council to ban sexual entertainment venues in the city.

“It was incredibly exciting to be involved in these cases so early in my career,” Ms McCosh says. “Since qualifying, which was less than a year ago, it’s been a real privilege to be part of this litigation team.”

There has been no let-up since she finished her traineeship, with Ms McCosh again working as part of a team representing Shelter when the charity challenged Glasgow City Council over its duty to provide suitable housing to a refugee couple whose son has special needs. The Supreme Court found in the family’s favour earlier this year. She was also involved last year when Stobo Residents Action Group’s successfully challenged Scottish Forestry’s decision to approve a commercial woodland project on the Stobo estate and is acting on a family case to do with the Children’s Hearing (Scotland) Act that is likely to go to the Supreme Court.

“I am so excited about this area of work,” Ms McCosh says. “Sindi is a really brilliant public and constitutional lawyer and Elaine Motion [partner and former chairman at Balfour & Manson] is a formidable public lawyer with an incredible history. There are lots of really brilliant litigators in the team at Balfour & Manson and in terms of my career it’s a dream come true working here. Being able to train in public law was very, very lucky in a lot of ways.”