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-siteRequirements:• Degree in Mechanical or Building Services Engineering, or relevant trade qualification• Minimum 4 years’ experience in mechanical contracting (data centres, industrial, pharm...