Principal Mechanical Engineer

As a Principal Mechanical Engineer, you'll play a pivotal role in one of the UK's major civil nuclear decommissioning programmes. Working as a senior technical authority within a multidisciplinary engineering environment, you'll drive the integration of complex mechanical systems and develop innovative solutions that directly support the safe deconstruction and long-term management of nuclear facilities.
You'll lead engineering teams, oversee high-integrity technical outputs, safeguard design quality, and act as a primary interface for customers-while mentoring engineers and championing continuous improvement across projects. This role places you at the technical forefront of a major expansion within the Cavendish Nuclear Design Services Alliance.
Day-to-day, you'll have the following responsibilities:

Lead and manage multidisciplinary engineering teams to deliver high-quality technical solutions
Supervise and mentor engineers and technical specialists to ensure performance and development
Act as a key liaison with customers, ensuring transparent communication and technical clarity
Oversee production, review, and approval of engineering outputs-including calculations, specifications, and reports
Champion safety, quality, and engineering best practice across all project activities.

This is a full-time position working 37 hours, 5 days per week, based at either of our Westlake's Science Park, Moor Row or Warrington, Cheshire sites.
Essential Experience

Extensive experience leading multidisciplinary engineering teams and delivering complex technical projects
Proven ability to supervise and mentor engineers and technical specialists
Strong background in producing, reviewing, and approving detailed engineering outputs
Demonstrated expertise in applying procedures, codes, and standards to ensure compliance and integrity
Track record of effective customer engagement, issue resolution, and technical support., Engineering degree (or equivalent) in a relevant engineering discipline.

Security Clearance
The successful candidate must be able to achieve and maintain Standard (BPSS) security clearance for this role. 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 is a benefit that allows UK Cavendish employees to buy additional leave or to sell up to one working week of annual leave from their annual 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.

Cavendish
We're Cavendish Nuclear - a team of 5,000 specialists and a core part of Babcock International Group.
Here, you'll be part of something bigger. Across clean energy, defence, and civil decommissioning, your work will contribute to projects that are critical to energy security and national protection. Together, we're shaping a future that lasts - not only through the impact we make, but through meaningful careers that respect your work-life balance.
Join us and discover how far we can go, together.