Principal Engineer - Mechanical Systems in Plymouth

Location: Plymouth + Hybrid Working Arrangements

Compensation: Competitive + Benefits

Role Type: Full time / Permanent

Role ID: SF69840

Lead complex mechanical systems engineering at the heart of the UK’s defence infrastructure. At Babcock we’re working to create a safe and secure world, together, and if you join us, you can play your part as a Principal Engineer – Mechanical Systems at our Devonport Royal Dockyard site.

The role involves:

• Maintaining and controlling modifications to mechanical building services across both nuclear-implicated and non-nuclear facilities.
• Spanning the full engineering lifecycle, from requirements capture and design development through implementation, close-out, through-life support, decommissioning and disposal.
• Shaping engineering solutions that underpin national defence, ensuring compliance with nuclear site licence conditions, regulatory frameworks and industry design standards.
• Collaborating with specialists across engineering disciplines, influencing project delivery from concept to completion, and helping develop innovative, safe and efficient systems.

Key responsibilities include:

• Ensuring compliance with nuclear site licence conditions, statutory legislation, regulatory frameworks and industry-recognised design codes.
• Prescribing the Mechanical Building Services requirements for assigned design projects.
• Developing and delivering design solutions across the full design process, including Start-up, Concept, Scheme, Detailed and Implementation phases.
• Supporting design reviews to ensure subcontractor designs meet company, regulatory and industry standards.
• Managing the production, checking and approval of technical documentation and engineering drawings.

This role is full time, 35 hours per week and provides hybrid working arrangements with a minimum of 2 days onsite.

Essential experience includes:

• Familiarity with energy reduction strategies and decarbonisation approaches for new and existing buildings, including passive design solutions.
• Extensive understanding of mechanical engineering principles for steam and condensate, industrial gases, fresh and demineralised water, HVAC (including nuclear-related), LEV and domestic services.
• Detailed knowledge and experience of BREEAM, DREAM and Building Regulations.
• Experience working within a design consultancy or contractor design environment, with the ability to manage a small team of engineers.
• Strong understanding of applicable regulations, legislation and technical standards related to mechanical services system design.

Qualifications:

• Degree-level qualification (Level 7) in Mechanical Engineering or Building Services Engineering, or a lower-level qualification with significant supporting experience.
• Chartered Engineer status with CIBSE or IMechE or working towards Chartered status.
• Additional mechanical systems, nuclear or building-services-related professional training or certifications - Desirable.

Security Clearance:

The successful candidate must be a sole UK national who is able to achieve and maintain Naval Nuclear Propulsion Information (NNPPI) security clearance for this role.

What we offer:

• Generous holiday allowance.
• Matched contribution pension scheme, with life assurance.
• Access to a Digital GP, annual health check, and nutritional consultations through Aviva DigiCare+.
• Employee share scheme.
• Employee shopping savings portal.
• Payment of Professional Fees.
• Reservists in the armed forces receive 10-days special paid leave.
• Holiday Trading allows UK Babcock employees to buy additional leave or to sell up to one working week of annual leave from their annual entitlement.
• ‘Be Kind Day’ enables employees to take one working day’s paid leave a year (or equivalent hours) to undertake volunteering work with their chosen organisation or registered charity.
• Excellent development opportunities and benefits package including an employee assistance programme supporting physical, mental and financial wellbeing.

Babcock International has helped to defend nations, protect communities and build a better world for over a century. We are a disability confident committed employer. If you have a disability or need any reasonable adjustments during the application and selection stages, please email careers@babcockinternational.com with the subject header ‘Reasonable adjustments requirement’. We’re committed to building an inclusive culture where everyone’s free to thrive. We are happy to talk about flexible working – please ask about alternative patterns of work at interview.

Closing date: 05/02/2026