Principal Mechanical Engineer

Principal Mechanical Engineer Up to £63.50 per hour | Outside IR35 | 12-Month Contract | 4-Day Working Week We are seeking an experienced Principal Mechanical Engineer to lead engineering design teams on complex,…

Outside IR35 Engineering
Pay rate £60 – £63.50/hour
Contract type Contract
Posted 13 October 2026

Trusted. Transparent. Built for contractors. Thousands of UK contractors find their next contract on ContractorUK.

View all engineering jobs ›

About this contract

Outside IR35

Principal Mechanical Engineer

Up to £63.50 per hour | Outside IR35 | 12-Month Contract | 4-Day Working Week
We are seeking an experienced Principal Mechanical Engineer to lead engineering design teams on complex, safety-critical projects within the nuclear sector. This role combines technical leadership, engineering assurance and project delivery, with a strong focus on UKCA/CE marking, regulatory compliance, verification and validation, and nuclear safety.
Contract details

Rate: Up to £63.50 per hour, outside IR35

Duration: 12 months

Hours: 40 hours per week, Monday to Thursday

Security: Ideally hold current SC clearance or be eligible to obtain it

Key Responsibilities

Lead and supervise mechanical engineering design teams, providing technical direction and oversight.

Plan and coordinate engineering activities, managing resources, budgets, schedules and delivery against project requirements.

Develop design basis documentation, identify engineering requirements and ensure nuclear and conventional safety principles are applied.

Oversee design risk assessments, technical interfaces and multidisciplinary engineering integration.

Ensure technical documentation supports UKCA/CE marking and demonstrates conformity with applicable legislation, regulations and standards.

Lead and record verification, validation and conformity assessment activities.

Conduct design reviews and check engineering deliverables for technical accuracy, quality and compliance.

Maintain awareness of the Machinery Directive, LOLER, PUWER, CDM and other relevant legislation.

Support project planning, tender responses, risk management and recovery strategies where delivery issues arise.

Promote continuous improvement, right-first-time quality and effective configuration control.

Mentor and develop engineers, support competency assessments and ensure effective allocation of engineering resources.

Essential Requirements

Relevant Level 6 qualification, such as a Bachelor's degree with honours in an engineering discipline.

Proven experience in mechanical engineering design and technical leadership.

Experience leading or supervising engineering teams within a complex engineering environment.

Strong understanding of engineering compliance, design assurance and verification and validation.

Experience with UKCA/CE marking requirements, including technical documentation and conformity assessment.

Knowledge of the Machinery Directive, LOLER, PUWER, CDM and applicable engineering standards.

Experience managing engineering deliverables, resources, schedules and technical risks.

Strong stakeholder management skills and a commitment to quality, safety and continuous improvement.

Desirable Experience

Experience within the nuclear industry or another highly regulated, safety-critical environment.

Experience with machinery, process plant or complex mechanical systems.

Familiarity with nuclear safety principles and multidisciplinary design integration.

Current SC security clearance, or eligibility to obtain it.
This is an excellent opportunity for a technically strong Principal Mechanical Engineer to lead engineering teams on a long-term contract, taking ownership of design quality, regulatory compliance and safe engineering delivery

Apply for this job

You'll complete your application on CV-Library, our jobs partner.

← More engineering jobs

Set up for this contract

ContractorUK partners
Markel Direct IR35 and contractor insurance

Most agencies and clients ask for professional indemnity and public liability before you start.

Get your quote →
SG Accounting Contractor accountants

Outside IR35 means working through your own limited company, so an accountant who knows contracting matters.

Find out more → Also: Caroola · Dolan Accountancy · Compare all accountants

Get new Engineering contracts by email

One email when new matches appear. Unsubscribe with one click.

Prefer to be found? Upload your CV to CV-Library — free