Principal Mechanical Engineer

-; Plymouth; On-site; GBP 125,000 - 150,000; Full time

Job summary

A leading defense infrastructure firm in Plymouth is seeking a Principal Mechanical Engineer to influence the design and development of critical facilities for the Royal Navy. You will review contractor designs and ensure compliance throughout the design lifecycle. This full-time role offers hybrid working arrangements and a competitive compensation package. Key qualifications include a degree in Mechanical Engineering and experience in design engineering.

Benefits

Generous holiday allowance

Matched contribution pension scheme

Access to Digital GP and health check

Employee share scheme

Holiday Trading options

Excellent development opportunities

Qualifications

• Previous experience in a senior engineering role with line management duties.
• Proven experience with MEP systems for industrial or building design.
• Ability to work in highly regulated environments.

Responsibilities

• Review and approve contractor designs for infrastructure projects.
• Ensure compliance with technical standards and project specifications.
• Collaborate with engineering managers and technical authorities.

Skills

Stakeholder engagement

Communication skills

Design engineering

CAD or BIM expertise

Education

Degree in Mechanical Engineering

Chartered Engineer status

Tools

Autodesk

Inventor

Job description

Job Title: Principal Mechanical Engineer

Location: Plymouth, Devon + Hybrid Working Arrangements

Compensation: Starting from £59,110 + Benefits

Role Type: Full time / Permanent

Shape the Future of 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 Mechanical Engineer at our Devonport Royal Dockyard site.

The role

As a Principal Mechanical Engineer, you'll be at the forefront of one of the UK's most significant infrastructure projects. This is your opportunity to influence the design and development of critical facilities that support the Royal Navy's future capability.

Day-to-day, you'll act as the intelligent customer, reviewing and approving contractor designs, ensuring compliance and excellence throughout the full design lifecycle.

• Reviewing, approving, and accepting mechanical designs for major infrastructure projects.
• Advising contractors and stakeholders to ensure technical integrity and compliance.
• Using CAD and 3D modelling tools (e.g., Autodesk, Inventor) to assess design proposals.
• Collaborating with technical authorities and engineering managers across Babcock.
• Supporting the growth of a specialist engineering team within Strategic Infrastructure.

This role is full time, 35 hours per week and provides hybrid working arrangements with 2 days in the office/onsite and 3 days working from home.

Essential experience of the Principal Mechanical Engineer

• Previous experience in senior engineering role, ideally with line management duties.
• Proven experience in MEP systems for industrial or building design.
• Strong background in design engineering, including CAD or BIM.
• Ability to operate in highly regulated environments.
• Excellent stakeholder engagement and communication skills.

Qualifications for the Principal Mechanical Engineer

• Degree-qualified in Mechanical Engineering (or equivalent).
• Chartered Engineer status preferred (or significant experience in lieu).
• Additional certifications in building services or nuclear environments advantageous.

Security Clearance

The successful candidate must be able to achieve Security Check (SC) clearance for this role.

Many of the positions within our company are subject to national security clearance and Trade Control restrictions. This means that your eligibility for certain roles may be affected by your place of birth, nationality, current or former citizenship, and any residency you hold or have held. Further details are available at United Kingdom Security Vetting: clearance levels - GOV.UK (www.gov.uk).

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 sell up to one working week of annual leave from their entitlement. This Window opens February through to March annually.
• ‘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

For over a century Babcock has helped to defend nations, protect communities and build a better world. To continue, we must adapt, advance and be a sustainable business with a shared goal.

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 [e-mail] with the subject header ‘Reasonable adjustments requirement’. We are 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: 27/11/2025