Principal Mechanical Engineer

Glasgow, United Kingdom / Altrincham, United Kingdom / Bristol, United Kingdom

Mott Mac Donald is a global engineering, management, and development consultancy with over 20,000 employees across more than 50 countries and 140+ offices.

We work across incredible global industries, delivering exciting work that is defining our future and making an important societal impact in the communities we serve. Our people power our performance – we succeed when they do. With countless opportunities to collaborate, learn, and grow, the possibilities for excellence are as varied as every individual.

Whether you want to grow as a subject matter expert or broaden your experience with roles across our international community, you’re surrounded by global specialists who want to combine their expertise and champion you to be your best. As a proudly employee‑owned business, we benefit our clients, our communities, and each other, investing in creating the right space for everyone to feel empowered, included, and valued.

Whatever your ambition, Mott Mac Donald is where people come to be brilliant.

The Energy unit delivers services to clients globally across several sectors including hydropower, nuclear, waste, renewable generation and transmission & distribution networks. Together we provide integrated engineering and project management services across the project lifecycle – from concept and design to construction and operations, to decommissioning or repowering and life extension. Together with our clients, we’re helping to deliver the energy transition globally.

We are looking for a Principal Mechanical Engineer to join our growing Nuclear;
Defence and Civil division. This role offers an exciting opportunity to work on a diverse portfolio of projects, including nuclear decommissioning, defence, and nuclear new build. You will collaborate with clients both locally and nationally while contributing to some of the most impactful energy and infrastructure projects in the industry.

This is a fantastic opportunity to play a key role in delivering solutions for the energy sector while advancing your career in a supportive and forward‑thinking environment.

Key responsibilities and duties include:

• Lead mechanical engineering aspects of multi‑discipline design projects, from feasibility to detailed design stages
• Work on a diverse range of projects, including nuclear decommissioning, defence, and energy infrastructure
• Liaise with clients to develop and deliver innovative solutions tailored to their needs
• Produce and oversee the creation of high‑quality design and technical documentation
• Provide quality assurance through surveillance, review, and checking of team outputs
• Collaborate with multi‑disciplinary teams to deliver fit‑for‑purpose engineering solutions
• Visit client sites as required and promote further opportunities to enhance client relationships
• Ensure safety is an integral part of mechanical engineering design and project delivery
• Present and defend solutions to complex problems in client‑facing environments
• Chartered status with the IMechE or other relevant professional body (or equivalent experience with progress toward chartered status)
• Demonstrable experience in mechanical engineering design within a highly regulated industry, preferably nuclear
• Broad knowledge of industry standards, legislation, and engineering principles
• Strong commercial awareness, with experience in FEED (Front‑End Engineering Design) projects
• Excellent communication skills and the ability to engage effectively with clients and stakeholders
• Capable of managing and prioritising multiple projects in a dynamic environment
• Client‑facing experience, with the ability to maintain and build strong client relationships
• Experience of leading, managing and working with multi‑disciplinary teams
• Proactive in seeking input from other engineers, specialists, and team members to enhance project outcomes
• Committed to continuous professional development and staying abreast of industry advancements

Please be advised that offers for this role are conditional upon obtaining the appropriate level of Security Clearance.

Mott Mac…