Senior Security Architect

As the Senior Security Architect, you will play a key role within the Information Security and Cyber Security team, helping to develop and maintain Thames Water's security architecture strategy, roadmaps, principles, standards, and reusable security patterns. You will provide security architecture leadership across strategic transformation and innovation programmes, ensuring secure-by-design practices are embedded throughout the technology delivery lifecycle.
Reporting to the Head of Security Architecture, you will work closely with security, technology, operational, and business stakeholders to ensure new and existing technology capabilities are designed and delivered with appropriate, proportionate, and effective security controls. This role requires deep technical expertise, strategic thinking, and the ability to influence architectural decisions, manage security risks, and strengthen cyber resilience across a regulated Critical National Infrastructure environment.
What you'll be doing as the Senior Security Architect

• Security Architecture Strategy: Support the development and maintenance of Thames Water's security architecture strategy, domain roadmaps, and target-state architectures, ensuring alignment with business objectives, technology strategy, and organisational security priorities.
• Security Domain Leadership: Act as a recognised subject matter expert across assigned cybersecurity domains, including Identity and Access Management (IAM), Privileged Access Management (PAM), Security Information and Event Management (SIEM), Security Operations Centre (SOC), Endpoint Detection and Response (EDR), Cloud Security, IT Security, and OT Security.
• Secure Solution Design: Lead security architecture workshops, design reviews, and assurance activities across projects and programmes, ensuring solutions are secure by design and aligned with approved security principles, standards, patterns, and the organisation's risk appetite.
• Security Architecture Artefacts: Develop, maintain, and govern security architecture principles, requirements, guardrails, technical standards, reusable patterns, reference architectures, and technical guidance to support consistent and repeatable security outcomes.
• Threat & Risk Assessment: Lead threat modelling, security risk assessments, and architecture risk identification activities, translating business, regulatory, and technical requirements into proportionate security controls and effective mitigation strategies.
• Security Control Assurance: Provide security architecture oversight throughout the technology delivery lifecycle, including architecture reviews, design authorities, stage-gate assessments, and go-live assurance, ensuring agreed security controls are implemented effectively.
• Collaboration Across Teams: Work closely with Enterprise Architects, Solution Architects, Security Engineering, Cyber Security Operations, project and programme teams, technology owners, business leaders, and OT stakeholders to embed security into strategic initiatives and operational environments.
• Security Governance & Compliance: Ensure alignment with recognised security frameworks and standards, including ISO 27001, NIST Cybersecurity Framework, CIS Controls, Cyber Assessment Framework (CAF), and Secure by Design principles, supporting compliance within a regulated Critical National Infrastructure environment.
• Vendor & Technology Evaluation: Provide security architecture expertise during technology procurement, product selection, and vendor assessments, ensuring proposed solutions meet Thames Water's security architecture requirements and support long-term security objectives.
• Security Capability Development: Contribute to the development of security capabilities, technology roadmaps, and operational improvements, promoting knowledge sharing, mentoring colleagues, and championing security-by-design principles and continuous improvement across the organisation.

Base location - Hybrid - Clearwater Court, Reading
Full Time - 36 hours per week
What you should bring to the role:
Essential Experience:

• Security Architecture Strategy: Extensive experience operating as a Security Architect within complex enterprise environments, developing security architecture strategies, roadmaps, and target-state architectures aligned with business and technology objectives.
• Security Architecture Delivery: Proven experience leading security architecture activities across the full solution lifecycle, from concept and design through implementation, transition, and operational service.
• Security Architecture Governance: Experience providing architecture assurance, design reviews, governance, and constructive challenge through architecture review boards, design authorities, technical reviews, and stage-gate approval processes.
• Security Risk & Threat Modelling: Demonstrable experience conducting structured threat modelling, security risk assessments, and control assurance activities across complex technology solutions, platforms, and services.
• Security Domain Expertise: Strong understanding of cybersecurity domains, with demonstrable depth of expertise in at least two areas, such as IAM, PAM, SIEM, SOC, EDR, Cloud Security, or IT Security.
• Cloud Security Architecture: Experience designing secure solutions across cloud, hybrid, and on-premises environments, with strong knowledge of Microsoft Azure and at least one additional public cloud platform, such as AWS or GCP.
• Security Frameworks & Standards: Experience applying recognised security frameworks, standards, and methodologies, including ISO 27001/27002, NIST CSF, CIS Controls, CAF, and Secure by Design principles.
• Stakeholder Engagement: Proven ability to lead security architecture workshops, influence technical and business decisions, and communicate complex security requirements to stakeholders at all levels.
• Security Architecture Artefacts: Experience developing and maintaining security principles, requirements, guardrails, technical standards, reusable patterns, reference architectures, and architecture documentation.
• Operational Security Alignment: Experience collaborating with Security Operations, Security Engineering, technology, and delivery teams to ensure architectural decisions translate into effective, maintainable, and resilient operational capabilities.
• Essential Skills & Qualifications:
• Technical Security Expertise: Strong knowledge of enterprise, solution, and technical security architecture practices, with the ability to apply secure-by-design principles across complex technology environments.
• Security Risk Management: Ability to translate business, legal, regulatory, and technical requirements into practical security controls, architectural decisions

What's in it for you?

• Competitive salary from of up to £86,000 per annum depending on experience
• Car Allowance £5,800
• Annual Leave - 26 days holiday per year increasing to 30 with the length of service (plus bank holidays)
• Performance-related pay plan directly linked to company performance measures and targets
• 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.

Find out more about our benefits and perks (Please note different T&Cs apply if on secondment)
Who are we?
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.
Learn more about our purpose and values
Working at Thames Water
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 meaningful career opportunities, flexible working arrangements and excellent benefits.
If you're looking for a sustainable and successful career where you can make a daily difference to millions of people's lives while helping to protect the world of water for future generations, we'll be here to support you every step of the way. Together, we can build a better future for our customers, our region, and our planet.
Real purpose, real support, real opportunities. Come and join the Thames Water family. Why choose us? Learn more.
We're committed to being a great, diverse, and inclusive place to work. We welcome applications from everyone and want to ensure you feel supported throughout the recruitment process. If you need any adjustments, whether that's extra time, accessible formats, or anything else just let us know, we're here to help and support.
When a crisis happens, we all rally around to support our customers. As part of Team Thames, you'll have the opportunity to sign up to support our customers on the frontline as an ambassador. Full training will be given for what is undoubtedly an incredibly rewarding experience. It's also a great opportunity to learn more about our business and meet colleagues click apply for full job details