An accomplished mediator and conciliator, Joanna brings 19 years of experience at Acas and a strong reputation as an expert in dispute resolution, facilitation and mediation. Since joining Acas in 2006, she has worked extensively with employers, trade unions and employees to foster constructive dialogue, resolve complex workplace issues and promote positive employment relations.

Over nearly two decades, Joanna has held a wide range of roles across the organisation, including helpline advisor, individual conciliator and mediator, internal trainer of conciliators and mediators, senior advisor, collective conciliator and, most recently, Assistant Chief Conciliator.

Jo officially took up the position of Chief Conciliator on Monday 3^rd November 2025.

The Chief Conciliator leads the team that helps unions and employers resolve disputes at work through Acas’s free, impartial and trusted collective conciliation service.

Niall Mackenzie, Acas Chief Executive, said:

“I am delighted to confirm Jo’s appointment as Chief Conciliator, following a very competitive open process.

“Jo has a huge amount of experience resolving conflicts and has brought her conciliation skills to bear on many high-profile disputes in recent years.

“This year marks Acas’s 50th anniversary in its current form, but its roots go back to 1896. That means we have been helping resolve workplace disputes for nearly 130 years.

“Against the backdrop of major employment reform, Jo’s expertise and leadership will be crucial to helping resolve disputes at work and continuing our long tradition of excellent service to both employers and workers.”‍

Joanna Nunn, Acas Chief Conciliator, said:‍

“I am pleased to take up the role of Chief Conciliator and lead a team of experts that handles over 500 disputes each year.

“Acas’s collective conciliation service is hugely successful at helping people find common ground and work through their differences.

“As the government rolls out a major package of employment law reform, the knowledge and skill of Acas’s collective conciliators is going to be more vital than ever.”‍

Joanna replaces previous Chief Conciliator Marina Glasgow, who held the position from May 2023 and was Acas’s first female Chief Conciliator.

In 2024 to 2025, Acas’s collective conciliation team facilitated confidential talks in over 522 disputes, resolving or supporting progress toward settlement in 93% of cases. Pay was the leading cause of disputes, and cases are down from 618 the previous year.