Networking & Security Engineer in London

We are seeking a hands-on Infrastructure & Security Engineer with deep expertise across security architecture, server, and network domains. Security is the core priority of this role. The successful candidate will take a leading part in strengthening and evolving the firm's security posture in response to an increasingly sophisticated threat landscape, including emerging risks associated with AI.

This is a technically demanding role that combines proactive security ownership with infrastructure delivery. The successful candidate will act as a security-first thinker across everything they touch, from day-to-day operations through to strategic infrastructure design, and will be expected to drive meaningful improvements to the firm's defensive capabilities.

This role is office-based and requires five days per week on-site presence.

Key Responsibilities

• Lead the firm's security operations function, owning threat detection, incident response, and vulnerability management end-to-end.
• Monitor, triage, and respond to security events across the environment, including log analysis, anomaly detection, and threat hunting, with a strong awareness of modern and AI-enabled attack vectors.
• Own and drive security hardening across all infrastructure — servers, endpoints, network devices, and cloud-adjacent systems — ensuring consistent application of best practices and compliance with security policies.
• Design and implement secure infrastructure solutions, embedding security requirements from the outset rather than retrofitting them.
• Conduct regular vulnerability assessments and penetration testing exercises, prioritising and remediating findings in a timely manner.
• Manage and continuously improve security tooling, including SIEM, EDR, firewalls, IDS/IPS, and endpoint protection platforms.
• Act as the escalation point for security-related incidents across 2nd and 3rd line, providing expert guidance and driving resolution.
• Support and maintain network infrastructure including firewalls, switches, VPNs, and wireless systems (primarily Cisco-based), with a security lens on all configuration and change.
• Operate across Windows and Linux (Red Hat/CentOS) environments, ensuring both are maintained to a consistent security baseline.
• Collaborate with infrastructure and technology teams to embed security into project delivery and BAU processes.
• Develop and maintain security documentation including incident response playbooks, SOPs, architecture diagrams, and runbooks.
• Stay current with the evolving threat landscape, bringing proactive recommendations to improve the firm's security posture over time.
• Participate in an on-call rotation to support critical systems and respond to security incidents outside business hours.

Requirements

• Minimum 7+ years’ experience in infrastructure, networking, and security roles.
• Strong hands-on experience with Windows Server and Linux (Red Hat/CentOS).
• Solid networking knowledge, including TCP/IP, VLANs, VPNs, DNS, DHCP, with practical experience in Cisco environments.
• Demonstrated experience implementing and supporting security controls, including patch management and system hardening, endpoint protection and monitoring, identity and access management.
• Good understanding of cyber security principles, including modern threat landscapes and evolving risks (e.g. automation and AI-driven attack vectors).
• Experience with virtualisation (VMware) and enterprise storage (SAN/NAS).
• Scripting or automation experience (e.g. PowerShell, Bash) is advantageous.
• Experience in financial services or regulated environments is preferred.
• Strong troubleshooting skills with a structured and analytical approach.
• Able to balance BAU responsibilities with project delivery effectively.
• A thoughtful and forward-looking mindset, with the ability to identify risks and propose improvements.
• Clear and confident communicator, able to engage with both technical and non-technical stakeholders.
• Self-motivated, accountable, and willing to take ownership of issues end-to-end.
• Collaborative and adaptable, with a practical and solutions-focused approach.