Cathy Maguire BL reviews the case of O’Connell v Building and Allied Trades’ Union, Edward Morris, Patrick O’Shaughnessy and Michael McNamara and the Construction Industry Federation [2014] IEHC 360; [2015] 26 ELR 173 (HC); [2016] IECA 338 (CA); : [2017] IESCDET 22 (SC), which illustrates the interaction between the closed shop and the Constitutional right to work. It demonstrates that while a union is entitled to approach an employer and ask that employer to engage only union members, and the employer is entitled to enter into an agreement with the union to that effect, the union cannot then wrongfully refuse membership to a qualified applicant and yet enforce the closed shop.