We are recruiting for a Mechanical Commissioning Engineer to join a specialist international sub-contractor on a high-profile data centre project in London. This is an excellent opportunity for an experienced engineer to take full ownership of commissioning activities from installation through to handover. Key Responsibilities: • Lead commissioning activities across all project phases, ensuring timely delivery and compliance with design • Create, manage, and track test packs, commissioning plans, and technical documentation • Oversee and witness Factory Acceptance Tests (FATs), Site Acceptance Tests (SATs), and internal snagging inspections • Coordinate and participate in pre-commissioning and system walkdowns using P&IDs and schematics • Manage the commissioning schedule in line with project deadlines, updating trackers and progress reports • Work closely with vendors, subcontractors, and internal teams to resolve technical issues and close out snags • Review and clarify technical queries with the design team and contribute to technical meetings • Ensure all commissioning activities align with EHS, quality, and operational standards • Support the production of O&M manuals and client handover documentation • Provide guidance and mentoring to junior engineers on-site Requirements: • Degree in Mechanical or Building Services Engineering, or relevant trade qualification • Minimum 4 years’ experience in mechanical contracting (data centres, industrial, pharma) • Strong technical understanding of commissioning and mechanical systems • Confident working with schematics, P&IDs, and quality standards • Strong communication, organisation, and problem-solving skills If you are interested in this role, please send over an updated C.V to (url removed)