Mitie Cleaning & Hygiene Services
Assistant Site Manager
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The Assistant Site Manager supports the Site Manager in the safe, efficient, and compliant delivery of Integrated Security System (ISS) projects within operational electricity substations and critical infrastructure environments. The role provides day-to-day leadership and coordination of site activities whilst ensuring technical installation works are completed to specification, programme requirements, quality standards, and client expectations.
The Assistant Site Manager acts as the primary operational link between the Site Manager and Technical Supervisors, ensuring that installation, commissioning, testing, and handover activities are planned and executed effectively.
Projects typically involve the installation, upgrade, integration, testing, and commissioning of:
- CCTV systems
- Access Control Systems (Gallagher)
- Intruder Detection Systems
- Perimeter Intrusion Detection Systems (PIDS)
- Fibre Optic Communications Infrastructure
- Security Networks
- Server-Based Security Platforms
- UPS Systems
- Network Video Recorders (NVRs)
- Associated containment, cabling, and infrastructure within live substation environments
Key Responsibilities
Site Delivery & Coordination
- Support the Site Manager in planning and delivering security and electrical installation projects.
- Coordinate daily site activities and ensure works progress safely and efficiently.
- Assist in managing subcontractors, suppliers, and installation teams.
- Monitor labour resources and productivity against project programmes.
- Ensure site works are completed in accordance with design drawings, specifications, and client requirements.
- Identify potential delays and implement corrective actions where required.
- Support project reporting and provide regular progress updates to the Site Manager.
Technical Management
- Provide technical support to Technical Supervisors and installation teams.
- Assist in resolving installation and integration issues across multiple systems.
- Verify installation quality and ensure compliance with approved standards.
- Coordinate commissioning activities and support system integration processes.
- Review technical documentation, drawings, and installation packs prior to works commencing.
- Ensure defects, technical issues, and design queries are identified and escalated appropriately.
Health, Safety & Environmental Compliance
- Promote a positive health and safety culture throughout all project activities.
- Assist in implementing construction phase plans, RAMS, permits, and site safety procedures.
- Conduct site inspections and safety observations.
- Ensure all personnel work in accordance with company and client safety requirements.
- Monitor housekeeping standards across work areas.
- Support incident investigations and corrective actions as required.
- Ensure compliance with CDM regulations and electrical safety requirements applicable to live substation environments.
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Quality Assurance
- Ensure installations are completed in accordance with project quality standards.
- Carry out installation inspections and quality checks.
- Support completion of test records, commissioning documentation, and handover packs.
- Assist with management of snagging activities and defect resolution.
- Ensure project documentation remains accurate and up to date.
Client & Stakeholder Management
- Maintain positive working relationships with clients, principal contractors, and project stakeholders.
- Attend site meetings and represent the project team when required.
- Support client inspections, witness testing, and system demonstrations.
- Assist with Site Acceptance Testing (SAT) and client handover activities.
- Contribute to maintaining high levels of customer satisfaction throughout project delivery.
Resource & Commercial Support
- Monitor material requirements and support procurement activities.
- Ensure equipment and materials are available to meet programme milestones.
- Assist with management of site costs and resource utilisation.
- Identify opportunities to improve efficiency and reduce project costs.
- Support the Site Manager with site records, variations, and project reporting.
Essential Competencies
- Experience supervising technical, electrical, or security installation projects.
- Good understanding of integrated electronic security systems.
- Experience working within utility, energy, infrastructure, or substation environments.
- Knowledge of CCTV, Access Control, Intruder Detection, Fibre Networks, Servers, UPS and associated infrastructure.
- Strong organisational and planning skills.
- Ability to coordinate multiple work activities simultaneously.
- Strong communication and leadership skills.
- Ability to work collaboratively with clients, engineers, and construction teams.
- Competent in reading technical drawings and specifications.
- Strong problem-solving and decision-making abilities.
- Knowledge of Microsoft Office applications.
- Full UK Driving Licence.
Desirable Competencies
- SSSTS or SMSTS qualification.
- ECS Card.
- First Aid at Work.
- Temporary Works awareness.
- CDM understanding.
- Gallagher Access Control knowledge.
- Security systems commissioning experience.
- Fibre optic installation and testing knowledge.
- CAD or drawing review capability.
- National Grid, SPEN, SSE, or DNO project experience.
- IOSH Managing Safely.
Key Performance Indicators (KPIs)
- Safe delivery of projects with zero reportable incidents.
- Achievement of project milestones and programme targets.
- Quality compliance and minimal snagging.
- Successful completion of SAT and client handovers.
- Efficient utilisation of labour and materials.
- Positive client feedback and stakeholder engagement.
- Compliance with company policies, procedures, and quality systems.
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Our Benefits
Our market-leading offering provides you with benefits that suit your lifestyle.
- We have a virtual GP on hand for you and members of your household. So you can get expert advice by video or phone without having to leave your home.
- We offer financial wellbeing assistance through our Salary Finance scheme. For example, you could access 50% of your earned pay before payday for a small fee. Salary Finance also offers competitive loans.
- When you join us, we’ll give you a link to our flexible lifestyle benefits platform, Choices. You might choose to purchase up to five extra days’ holiday each year. You might buy critical illness insurance, seek dental treatment or buy technology products at an affordable cost. There are many choices!
- We give you access to high street discounts from thousands of well-known retailers, gyms and more through our MiDeals platform. And we have a cycle-to-work scheme.
- Life cover of up to four times your salary is available. We also offer enhanced pension contributions, a save-as-you-earn scheme, and a Mitie Matching Share Plan (you could even be awarded free shares in Mitie).
- We award our employees with Mitie Stars as recognition for their hard work. There are cash prizes up for grabs each month and at the end of the year there’s a chance to scoop a top prize of £10,000!
Our success is a direct result of the experience and quality of our people. Progressing your career is therefore a top priority for us. We offer a diverse variety of training and development avenues via a wide selection of learning resources to suit you.
We are committed to ensuring our recruitment process is inclusive and accessible to all. If you have a disability or long-term condition (for example dyslexia, anxiety, autism, a mobility condition or hearing loss) and need us to make any reasonable adjustments, changes or do anything differently during the recruitment process, please let us know by emailing at.
Since 1987, Mitie’s 84,000 employees have been maintaining companies globally. We are the UK’s leading facilities management and professional services company, and our clients range from household names in banking, critical government sites as well as hospitals and schools.
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