Principal Mechanical Design Engineer Location: Derby Agile / Hybrid Working Salary: Competitive + Bonus + Excellent BenefitsLead Mechanical Design on Complex, Low-Carbon Building ProjectsThis is a key hire within a growing building services consultancy, offering the opportunity to take ownership of mechanical design delivery across technically challenging, multi-sector projects.You will operate as a project leader and technical authority, influencing design standards, mentoring engineers, and working directly with clients across the full project lifecycle.With a strong pipeline of sustainable, design-led projects, this role offers both technical depth and clear progression into senior leadership.What''s on OfferClear progression pathway into senior leadershipAgile / flexible working modelGenerous annual leave (with buy/sell options)Enhanced family leave policiesCycle to Work and Electric Vehicle schemesEmployee Assistance Programme and wellbeing supportExposure to technically challenging, sustainability-focused projectsRegular team, social, and charitable initiativesThe RoleLead mechanical design delivery across projects, from concept through to completionAct as Project Leader, managing design coordination and client interactionProduce and oversee calculations, specifications, and detailed design outputsDrive technical excellence within the team, mentoring junior engineersContribute to low-carbon and sustainable design strategies, including renewable integrationAttend and lea