STEM Recruitment Solutions has partnered exclusively with a valued client who is seeking an experienced Principal Scientist to provide scientific leadership and hands-on expertise within a GMP-regulated manufacturing facility. This is a senior scientific role combining strategic influence, technical authority, management of a small team and active laboratory contribution, supporting a diverse portfolio of client projects across small molecules and emerging modalities. As a Principal Scientist, you will shape and lead analytical strategy across a diverse portfolio of client projects in a GMP environment, combining hands‑on laboratory work with senior scientific leadership. You will design, execute, and interpret complex analytical studies, delivering high‑quality, compliant data that supports process development, technical investigations, and informed decision‑making. Working closely with process chemists, project teams, quality colleagues, and clients, you will act as a trusted scientific partner, collaborating across disciplines to solve challenging technical problems and ensure analytical approaches are robust, fit for purpose, and aligned with regulatory expectations. Alongside project delivery, you will model scientific excellence, uphold the highest standards of safety and quality, and actively mentor and develop colleagues, helping to strengthen analytical capability, innovation, and scientific culture across the org...