Network Security Lead

We are looking for a security-focused, results-oriented individual who thrives in a collaborative, team-focused culture. You will work closely with IT and OT network managers, suppliers, business stakeholders, service owners, and your team to ensure the delivery of secure, reliable, and resilient network services across Thames Water. We are seeking a Network Security Manager to lead and manage the end-to-end BAU (Business As Usual) service delivery for network security across Operational Technology (OT) and Information Technology (IT). You will be responsible for maintaining robust security controls, managing suppliers, mitigating operational risk, and ensuring compliance with industry standards to protect Thames Water’s critical infrastructure.

What you’ll do as a Network Security Manager:

• Network Security Management: Maintain oversight of IT and OT network systems, including VPNs, SDWAN, and firewalls. Ensure all network security services are fit for purpose and aligned with business outcomes. Approve and manage all changes affecting the network threat surface.
• Governance & Compliance: Ensure network environments comply with regulatory obligations (NIST, CAF, etc.). Apply cybersecurity standards and maintain systems according to approved design.
• Service Delivery & Operations: Lead key service management processes (Continuity, Capacity, Availability). Attend incident/problem bridges as the subject matter expert. Review root cause analyses (RCAs) and oversee corrective actions. Provide accurate monthly service performance reports across IT and OT.
• Supplier & Financial Management: Lead and manage suppliers to meet agreed SLAs and KPIs. Ensure robust contractual requirements are in place for quality service delivery. Own and manage a £2M technical cost centre, driving efficiency and cost containment. Support the integration of £140M capital schemes into BAU operations.
• Risk & Change Management: Collaborate with the Operational Risk Manager to identify, mitigate, and report on network-related risks. Ensure all risk KPIs and improvement criteria are met.
• Leadership & Strategy: Lead and mentor a team of four security network engineers. Foster a collaborative culture aligned with the CTO’s technology strategy. Support programme delivery while safeguarding operational environments. Develop and execute sourcing strategies for sustainable service delivery.
• Collaboration & Continuous Improvement: Serve as the single point of contact for business and supplier stakeholders. Define and monitor SLAs, holding partners accountable for delivery. Drive continuous service improvement initiatives and manage CMDB updates.

What you should bring to the role:

• Essential Experience: Ability to gain SC Clearance. IT and OT network security experience. Strong interpersonal skills and stakeholder engagement capability. Proven problem-solving and decision-making skills. Experience with delivery methodologies (ITIL, waterfall, agile, lean). Ability to explain complex network issues simply and effectively.
• Essential Technical Skills & Qualifications: CCNP, CCNA or equivalent experience. CheckPoint CCSE, CCSA or equivalent experience. Proficiency in Layer 2/3 technologies (VLAN, RSTP, BGP, MRP) across vendors (Cisco, Meraki, Belden, Fortinet). Experience with network edge security (SDWAN, IPSEC) using tools like Cisco ISE, CheckPoint, and Umbrella. Higher education qualification or equivalent experience in engineering. Skills in stakeholder management, communication, and strategic decision-making.
• Desirable Experience: Previous experience in utilities or large-scale enterprises (20,000+ devices). Commercial acumen and change management experience. Ability to simplify complex network architecture for non-technical audiences.
• Desirable Technical Skills & Qualifications: Knowledge of network security technologies and strategic supplier management. Experience in stakeholder analysis and business case development. Familiarity with cloud integration (Azure and AWS).

What’s in it for you?

• Competitive salary up to £75,000 per annum, depending on experience.
• Annual Leave - 26 days holiday per year increasing to 30 with the length of service (plus bank holidays).
• Generous Pension Scheme through AON.
• Access to lots of benefits to help you take care of you and your family’s health and wellbeing, and your finances – from annual health MOTs and access to physiotherapy and counselling, to Cycle to Work schemes, shopping vouchers and life assurance.

We’re the UK’s largest water and wastewater company, with more than 16 million customers relying on us every day to supply water for their taps and toilets. We want to build a better future for all, helping our customers, communities, people, and the planet to thrive. It’s a big job and we’ve got a long way to go, so we need help from passionate and skilled people, committed to making a difference and getting us to where we want to be in the years and decades to come.

Thames Water is a unique, rewarding, and diverse place to work, where every day you can make a difference, yet no day is the same. As part of our family, you’ll enjoy fast-tracked career opportunities, flexible working arrangements and excellent benefits.

Our overarching aim is to ensure that Thames Water is a great, diverse, and inclusive place to work. We welcome applications from everyone and offer extra support for those who need it throughout the recruitment process. Our aim is to remove any real or perceived barriers to success, so if you need assistance, we’re here to help and support.