Job Title: Senior Network Engineer Location: London / Hybrid Type: Full-Time, Permanent We are working with a leading IT services organisation that supports enterprise clients across complex, business-critical environments. They are looking to appoint a Senior Network Engineer to join their network operations function, focusing on the support, stability, and continuous improvement of customer infrastructure. This role is well suited to an experienced engineer who enjoys working in live environments, troubleshooting complex issues, and ensuring high levels of network performance and availability. The Role As a Senior Network Engineer, you will play a key role in the ongoing operation of enterprise network environments. Acting as a senior escalation point, you will be responsible for resolving complex incidents, driving service improvements, and maintaining robust and secure network services. Key Responsibilities * Provide 3rd/4th line support across enterprise network environments * Act as an escalation point for complex incidents, problems, and major outages * Troubleshoot and resolve issues across routing, switching, and network security technologies * Proactively monitor performance and implement improvements to enhance reliability and efficiency * Conduct root cause analysis and implement long-term fixes to prevent recurring issues * Support and implement network changes in line with change management processes * Maintain and improve technical documentation, operational procedures, and runbooks * Work closely with service desk, NOC, and engineering teams to ensure effective service delivery * Contribute to continuous improvement initiatives across network operations * Provide guidance and mentorship to junior engineers where required Skills & Experience Required * Proven experience supporting complex enterprise network environments * Strong technical expertise in Routing & Switching (e.g., Cisco Catalyst, Nexus, SD-WAN, DNA Centre) * In-depth knowledge of routing protocols including BGP, OSPF, and IS-IS * Demonstrable experience troubleshooting in live, high-availability environments * Experience with data centre networking technologies and SD-Access * CCNP (or equivalent level of experience) Desirable Skills * Experience with network security technologies (e.g., ISE, ASA, FirePOWER) * Cisco wireless experience (support and troubleshooting) * Familiarity with monitoring and telemetry tools * Experience working within ITIL-based support environments Additional Information This is an opportunity to join a well-established organisation supporting a range of enterprise clients. The role offers exposure to large-scale environments and the chance to play a key role in maintaining and improving critical network services