Principal Mechanical Engineer

Job Title: Principal Mechanical Engineer

Location: Warrington, Cheshire or Preston, Lancashire + Hybrid Working Arrangements

Compensation: Competitive Salary + Benefits

Role Type: Full time / Permanent

Role ID: SF

Lead the engineering solutions shaping the future of nuclear projects

At Cavendish Nuclear, we’re working to create a safe and secure world, together. If you join us, you can play your part as a Principal Mechanical Engineer within our Business Winning team, based at either Warrington or Preston, with flexible hybrid working.

This is a pivotal role where you’ll lead the development of innovative mechanical engineering solutions during the bid phase – and then see those solutions brought to life as projects transition into delivery. It’s a rare opportunity to influence outcomes from concept to execution in one of the UK’s most critical sectors.

The role

As a Principal Mechanical Engineer, you’ll be accountable for leading the mechanical engineering input into major bids and proposals, ensuring robust, safe, and commercially competitive technical solutions. Working closely with internal stakeholders and external partners, you’ll shape winning submissions that support long‑term growth across clean energy, defence, and nuclear decommissioning.

Day-to-day, you will be:

• Leading the mechanical engineering development of innovative technical solutions for bids and tenders
• Owning the engineering scope, schedule, and delivery plans to meet customer and business requirements
• Ensuring technical integrity, compliance with standards, and application of best engineering practice
• Collaborating with multidisciplinary teams, partners, and the supply chain to deliver robust bid solutions
• Providing technical leadership and assurance across bidding activity and transition into project delivery

The role is full time working 37 hours per week and can be based at Warrington, Cheshire or Preston, Lancashire with hybrid working patterns available. Occasional travel to other business or customer sites may be required.

Essential experience of the Principal Mechanical Engineer:

• Proven experience leading mechanical engineering activities within complex projects or bids
• Experience managing engineering teams and coordinating multidisciplinary inputs
• Integration with safety case development, or similar process in other high hazard environments
• Design of remote operated Mechanical handling equipment and design of wet process plants
• Knowledge of mechanical engineering lifecycle (concept, design, manufacture, installation, commissioning and decomissioning.)

Qualifications for the Principal Mechanical Engineer:

• Engineering degree (or equivalent) in a relevant engineering discipline
• Chartered Engineer status, or working towards chartership
• Excellent communication skills with the ability to influence at all levels.

Security Clearance

The successful candidate must be able to achieve and maintain Standard (BPSS) / Security Check (SC) 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. 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, specialists and a core part of