Senior Mechanical Engineer in London

Location: Whitehaven, Cumbria + Hybrid Working Arrangements

Compensation: Competitive Salary + Benefits

Role Type: Full time / Permanent

Lead the Engineering That Shapes the Future of Nuclear Decommissioning

At Cavendish Nuclear, we are working to create a safe and secure world, together. If you join us, you can play your part as a Senior Mechanical Engineer at either of our Westlake's Science Park, Moor Row or Warrington, Cheshire sites.

As a Senior Mechanical Engineer, you will be a key contributor to one of the UK's major civil nuclear decommissioning programmes. You will take a leading role within a multidisciplinary engineering team, applying advanced technical expertise to develop, integrate, and enhance complex mechanical systems that directly support the safe deconstruction and futureproofing of nuclear facilities. Your work will influence high impact engineering decisions, ensuring compliance, technical excellence, and robust design integrity across the full project lifecycle. You will also support the development of junior engineers, collaborate across functions, and help shape best practice engineering within one of the most respected nuclear design alliances in the UK.

Day-to-day, you will have the following responsibilities:

• Lead the delivery of complex mechanical engineering tasks and provide high quality technical guidance
• Produce and review engineering documentation, including calculations, drawings, models, and reports
• Build strong relationships with customers and act as a key technical interface
• Apply relevant procedures, codes, and standards to ensure safety, compliance, and technical rigour
• Identify and manage project risks while contributing to safety assessments and continuous improvement initiatives.

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:

• Proven experience delivering engineering activities across the full project lifecycle
• Strong track record of producing and reviewing detailed engineering documentation
• Demonstrated ability to work effectively in multidisciplinary teams
• Excellent communication skills with confidence engaging customers and stakeholders.

Qualifications:

• 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.

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.
• 2 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.

About Cavendish Nuclear:

We are Cavendish Nuclear – a team of c5,000 specialists and a core part of Babcock International Group. Here, you will 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 are 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.

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 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: 17/02/2026