Job Description Are you ready to step into a defining leadership role, shaping the UK’s most critical infrastructure and engineering programmes through data excellence? At Assystem, we deploy expert teams into some of the country’s most complex and high-impact programmes across energy, defence, nuclear, and transportation. As we scale our data capability to meet growing demand, we’re looking for a Principal Data Engineer to lead delivery, set technical direction, and inspire a multi-disciplinary team of data professionals on projects of national importance. This is your opportunity to own the data function across high-stakes client engagements and act as both technical authority and strategic lead — ideal for a Senior Data Engineer ready to make the leap into a pivotal leadership position. Your missions: As our Principal Data Engineer, you’ll: Lead and support cross-functional data teams (engineers, analysts, scientists) on complex, high-value programmes. Design and deliver robust, secure, and scalable enterprise data solutions tailored to client goals. Define and uphold data architecture, pipeline, and modelling best practices across projects. Mentor and develop both senior and junior team members, fostering a high-performance culture. Represent data delivery in client governance and technical steering groups. Champion modern data practices: automation, metadata management, governance, and quality. Bridge the tactical and strategic, ensuring delivery is aligned with long-term client visions. Why join the community of Switchers? As one of the Top 3 Nuclear Engineering companies in the world, Assystem offer a competitive benefits package which includes: 25 days of annual leave bank holidays 8% company pension contributions Healthcare cash-plan to get money back on dental, medical, physical care Employee assistance programme including 24/7 access to free mental health support, virtual gym classes and more Get professional and industry membership fees paid for.