Iain Birrell is a member of the Employment Matters team at Thompsons Solicitors, based in Leeds.

As practice lead of Thompsons' Trade Union Law Group (TULG), Iain Birrell specialises in all areas of trade union law, such as industrial action, recognition, rule book issues, and elections. His specialisms encompass individual employment law, collective employment law, trade union constitutions, judicial reviews, CAC work, certification officer work, injunctions, and head office staffing matters.
In a previous role as regional manager, Iain was involved in the successful conclusion of mass equal pay-related sex discrimination cases in the North East, even obtaining a costs award against the other side's representative. Iain was appointed as a regional head of employment in 2007, during which time the Legal 500 called him "the key figure" in the Newcastle Office, while Chambers said he was "the practice's leading light in the North East and sources highlight his specialism in trade union discrimination and large-scale collective claims".
In 2014, he became the national case management coordinator for the firm's specialist Trade Union Law Group, which advises trade unions at head office level in connection with complex issues and handles important or sensitive disputes. Iain specialises in constitutional issues, as well as policy and public affairs work, and in 2014, gave evidence to the House of Commons' Small Business, Enterprise and Employment Public Bill Committee on the effects of the proposed legislation relating to zero hours contracts, whistleblowing, and financial penalties for unpaid employment tribunal awards.
He has also been a guest commentator for legal online information organisation Lexis Nexis, a division of the international publishing house Reed Elsevier.
After qualifying at a Yorkshire law firm, he spent some time in London providing legal input to the Channel Tunnel high speed rail link project.
Prior to joining Thompsons Solicitors in 2001, Iain had been a partner at the Yorkshire firm where he had specialised in commercial litigation and employment law.
Iain gives talks and lectures on employment law to clients both at events organised by Thompsons Solicitors and external organisations including the Institute of Employment Rights. Iain has been a guest author for LexisNexis, ACAS, LELR and USI, and has also lectured or run education events for most major trade unions, IER, and Legal Island, among others.
At his previous firm, Iain had 'batted for the other side' in employment law cases, as he puts it, but now enjoys being 'on the side of the angels' with Thompsons Solicitors. He is proud of making a difference on behalf of both individual union members and their unions. His previous legal experience inevitably gives him a valuable insight into arguments employers will make before they make them.
Away from work, Iain enjoys road cycling and covers some 3,500 miles a year with a cycling club.
Iain has been a member of the Law Society of England and Wales' employment law committee since 2008, which identifies areas of employment law and procedure that require reform or review and formulates recommendations for consideration by government and non-government bodies.
Since 2017 Iain has been an elected member of the Industrial Law Society's Executive Committee.
It has been a privilege to have met you and had your support throughout this.
Jonathan Duxbury, Iain's former client
Many thanks to you all for your various contributions which got us to this point. There are potentially 400,000 workers who could benefit from this judgement in a variety of ways. It is a tremendous result.
Paul O'Connor, National Officer of PCS
Thompsons has a knack of getting on particularly well with clients and managing their expectations.
Chambers
Thompsons fields a top-notch trade union practice.
Chambers
Thompsons has a strong hold on trade union instructions, delivering strategic employment law advice to UNISON, Unite, the GMB and the RMT.
Legal 500
Iain Birrell is a genius, both in terms of his formidable knowledge of employment law and his creative application of it to devise and implement a successful strategy for his trade union clients. He is immensely experienced in particularly novel and complex trade union cases of strategic importance. Having worked with him on many cases, his legal analysis is second to none.
Legal 500 2026.