Principal Mechanical Engineer

Location: London, UK (Head Office with European project exposure)
Salary: Competitive + benefits package

Join a rapidly expanding engineering consultancy driving high-performance mission-critical design.

Our client is a specialist engineering consultancy delivering Mechanical, Electrical and Public Health (MEP) design for hyperscale, colocation and mission-critical facilities across Europe and the Middle East.

With advanced capability in computational modelling, high-density cooling design, energy optimisation and BIM-coordinated engineering, they support some of the most technically demanding data-centre and critical-infrastructure projects in the market.

As part of their continued growth, they are seeking a Principal Mechanical Engineer to lead mechanical design excellence, drive technical innovation, and contribute to strategic project delivery across major mission-critical programmes.

About the Role

The Principal Mechanical Engineer will lead mechanical engineering design across large-scale, high-reliability environments. You will provide senior technical direction, coordinate multidisciplinary teams, ensure design compliance, and represent the consultancy in client-facing settings from early concept through to commissioning.

This role requires deep expertise in mechanical systems for mission-critical infrastructure — including cooling design, airflows, heat rejection systems, resilience strategies and high-density environmental control.

Key Responsibilities

• Lead mechanical design for mission-critical and data-centre projects, ensuring robust, efficient and scalable engineering solutions.
• Produce and review high-quality technical documentation including HVAC schematics, air-side and water-side designs, load calculations, performance modelling and equipment schedules.
• Develop high-density cooling strategies, energy-efficient mechanical systems and resilient mechanical architectures for 24/7 uptime environments.
• Coordinate closely with electrical, architectural, BIM, CFD and sustainability teams to deliver fully integrated MEP solutions.
• Manage, mentor and develop mechanical engineers, ensuring strong technical growth and high design standards.
• Attend and lead meetings with clients, contractors and project partners; present mechanical design rationale and technical recommendations.
• Support fee proposals, resource planning, project forecasting and strategic input to senior leadership.
• Conduct site visits, respond to technical queries and ensure mechanical design intent is maintained throughout construction and commissioning.

Qualifications & Experience

• Degree in Mechanical Engineering (or related discipline); Chartered Engineer status ideal or in progress.
• Minimum 10 years’ mechanical design experience, ideally within mission-critical, industrial, or data-centre environments.
• Strong expertise in HVAC design, chilled-water and DX systems, heat rejection technologies, airflow management and high-density cooling solutions.
• Experience delivering multidisciplinary projects across all RIBA stages, including involvement in construction and commissioning.
• Familiarity with performance modelling, airflow simulation interpretation (in collaboration with CFD teams), and energy optimisation for mechanical systems.
• Strong understanding of building services integration, control strategies and resilience design.
• Proven leadership skills, with the ability to mentor engineers and coordinate teams across multiple projects.

Why Apply?

This is a unique opportunity to join a high-growth consultancy delivering engineering for some of Europe’s most advanced mission-critical projects.

You will lead mechanical engineering strategy, shape high-density cooling solutions, influence project outcomes from the earliest stages, and help drive the firm’s growth in the data-centre and critical-infrastructure sectors.