Job Description

Closing Date

2026-12-01

Job Title: Lead Architect - NIS Programme

Location: Falmer or Durrington – Hybrid working (2 days a week)

Hours: 37 hours per week

Salary: depending on skills and experience

We're looking for an experienced Lead Architect to play a pivotal role in one of our most significant operational technology transformation programmes.

As the architectural lead for our NIS programme, you'll be responsible for defining and governing the overall technology architecture, ensuring solutions across Operational Technology (OT), IT, data, security, and integration are aligned, secure, and fit for purpose. You'll act as the key architectural authority, providing technical leadership, driving design decisions, and ensuring compliance with enterprise standards and regulatory requirements.

What will you be doing?

• Lead architecture across a complex, business-critical programme.
• Define and maintain the end-to-end architecture roadmap and key design decisions.
• Ensure alignment across OT, IT, security, data, and technology domains.
• Establish and chair architecture governance and design assurance activities.
• Review and challenge designs from internal teams, system integrators, and third-party vendors.
• Identify and manage architectural risks, dependencies, and cross-programme impacts.
• Work closely with programme leadership and delivery teams to align technology decisions with business outcomes.
• Act as the primary architectural advisor for stakeholders across the programme.

What are we looking for?

We're seeking a highly experienced architect with a strong background in Operational Technology environments and large-scale transformation programmes.

You'll bring:

• Significant experience designing and governing OT and industrial control system environments.
• Strong knowledge of SCADA, PLC, DCS, RTU, HMI and historian technologies.
• Experience of OT networking, segmentation, firewalls and Purdue Model principles.
• Understanding of industrial protocols such as OPC-UA, Modbus/TCP, DNP3, PROFINET and Ethernet/IP.
• Strong knowledge of OT cyber security standards including IEC 62443, NIST, ISO 27001 and NIS requirements.
• Experience integrating OT platforms with enterprise IT, cloud, data and monitoring solutions.
• Proven experience leading architecture across complex programmes or business transformations.
• Excellent stakeholder engagement, governance and decision-making skills.

Desirable

• TOGAF or equivalent architecture certification.
• Security certifications such as CISSP, CISM, GICSP or ISA/IEC 62443.
• Experience working within regulated, critical infrastructure, utilities, energy or transport environments.

Why Join Us?

This is an opportunity to shape the architecture of a major transformation programme that underpins essential services for our customers and communities. You'll work alongside senior stakeholders, influence strategic technology decisions, and help build secure, resilient and future-ready operational technology environments.

At Southern Water, we're committed to creating an inclusive workplace where everyone can thrive, bringing their authentic selves to work and contributing to meaningful change.