Senior 3rd Line Infrastructure Engineer

Leidos LLC; Huntingdon; On-site; GBP 47,000 - 79,000; Full time

Benefits offered by this job

Contributory Pension

Private Medical Insurance

33 days annual leave

Flexible benefits

Flexi-Time

Diversity & inclusion commitment

Job summary

Leidos UK is seeking a Senior 3rd Line Engineer to provide high‑level IT system support, incident resolution, and problem management for critical national security outputs. Responsibilities include proactive maintenance of the JUNO system, advanced troubleshooting, and stakeholder liaison at all levels.

The role requires expertise in virtualization, VDI, storage, backup, Windows and Linux, networking, and cloud‑native platforms.

Qualifications

• Extensive knowledge of virtualized environments and VDI.
• Strong Windows Server and Linux system administration experience.
• Solid networking, backup, and storage technologies knowledge.
• Ability to diagnose complex issues and document solutions clearly.

Responsibilities

• System support and incident resolution for Cat A systems to meet SLAs.
• Root cause analysis with other resolver groups and manufacturers.
• Periodic maintenance and system upgrades to mitigate obsolescence.
• Create/update system configuration documentation and change records.
• Assist in deployment and integration of infrastructure components.
• Participate in infrastructure projects and CRs.

Skills

Virtualized environments

VDI environments

HCI technologies

SAN storage

Backup & recovery

Windows Server 2008-2025

Linux administration

TCP/IP & networking

SDN / NSX-T / Arub a

Microsoft stack

Cloud-native platforms

Kubernetes & Docker

Scripting

Documentation skills

Analytical thinking

Communication skills

Education

ITIL Foundation

Tools

VMware

Hyper-V

NetApp

Nutanix

Veeam

Commvault

Active Directory

SharePoint / Teams / MS SQL

SCCM / SCOM

VMware NSX-T

Job description

Senior 3rd Line Engineer Location: Huntingdon, UK Clearance - High - DV 'Developed Vetting' UNLEASH YOUR POTENTIAL You will provide a crucial role in Core Services, conducting complex fault rectification of incidents, support Problem Management, Continual Service Improvement (CSI), and occasional Change Request (CR) work on IT Systems supporting key National Security outputs.

You will conduct reactive and proactive maintenance, primarily on the JUNO system, but may occasionally be required to support other systems that Leidos manage. These systems are highly utilised with many active users who operate at varying security levels. 3rd Line Engineers are responsible for responding to escalations from 2nd Line Engineers as well as other Resolver Groups and conduct advanced troubleshooting to diagnose and rectify issues as they arise. 3rd Line Engineers will be able to develop technical solutions to complex issues and problems as well as possess the ability to liaise with stakeholders at all levels of seniority, including the customer. Adherence to resolving issues and problems within SLA levels and ensuring KPI’s are met is also required. 3rd Line Engineers will;

• Have excellent knowledge of Virtualized Environments such as VMware and Hyper‑V.
• Have excellent knowledge of VDI environments such as VMware Horizon or Citrix.
• Have excellent knowledge of HCI such as NetApp SolidFire or Nutanix.
• Have excellent knowledge of SAN storage technologies such as NetApp or Dell PowerStore.
• Have excellent knowledge of Backup & Recovery technologies such as Veeam or Commvault
• Have excellent knowledge of Windows Server Environments from Server 2008 – 2025 including AD, DNS, DHCP and GPO from design to implementation and support.
• Have demonstrable experience of supporting Enterprise IT hardware in datacentre environments.
• Have strong Linux system administration skills (Ubuntu / CentOS/RedHat).
• Have strong knowledge of TCP/IP and networking technologies including load balancing and firewalls.
• Have strong knowledge of software defined network such as VMWare NSX‑T or HPE Aruba.
• Have good knowledge of Microsoft stack technologies such as SharePoint, Skype / Teams, MS SQL, MS System Centre, Office365, SCCM & SCOM, MS Exchange & CLI tooling .
• Have general knowledge of cloud‑native application platforms and Kubernetes‑based containerised applications.
• Have experience working on Production, Reference & Development systems & the configuration control lifecycle going from development through into production.
• Have experience MicroServices architecture platforms (Tanzu, Rancher), Kubernetes & Docker.
• Have knowledge of 2 Factor-Authentication technologies.
• Have knowledge/ experience with scripting.
• Have experience of producing and updating technical documentation to a high standard.
• Have excellent analysis and problem-solving skills.
• Possess excellent communication skills.
• Have ITIL3 or ITIL 4 at the Foundation level or above.

Key Duties

• System Support & Ticket resolution - Utilising technical expertise to ensure Cat A systems are kept online and running smoothly and that Incidents are dealt with in a timely manner IAW with KPI/SLA.
• Problem Resolution- Work with other resolver groups, original manufacturers, Users and suppliers to perform root cause analysis, providing technical solutions to complex problems.
• Maintenance - Responsible for completing the and recording Periodic maintenance of the system Utilising Periodic Preventative Maintenance (PPM) and routine upgrading activities to stay ahead of obsolescence issues.
• Documentation - Maintain and create documentation of system configuration changes. As well as accurately recording work in SD+
• Resource Movement - Assist in the configuration, installation, and deployment of infrastructure components, including virtual machines and UAD’s.
• Participation in Projects - Engage in infrastructure-related projects, CR’s contributing to implementation build, testing phases.

Key Competencies

• Communications - Verbal, written including technical documentation.
• Collaboration - Working with other SME’s, Users & Resolver groups to ensure efficiency.
• Adaptability and flexibility - Able to change focus under changing situations.
• Technical expertise - Ability to troubleshoot and fault rectification variety of issues.
• Attention to detail - Including written and work carried out.
• Customer service - excellence.
• Teamwork - Build effective internal and external relationships.
• Attention to detail - Including written and work carried out.
• Customer service - excellence.
• Teamwork - Build effective internal and external relationships.

What we do for you:

At Leidos we are PASSIONATE about customer success, UNITED as a team and INSPIRED to make a difference. We offer meaningful and engaging careers, a collaborative culture, and support for your career goals, all while nurturing a healthy work-life balance. We provide an employment package that attracts, develops and retains only the best in talent. Our reward scheme includes:

• Contributory Pension Scheme
• Private Medical Insurance
• 33 days Annual Leave (including public and privilege holidays)
• Access to Flexible benefits (including life assurance, health schemes, gym memberships, annual buy and sell holidays and a cycle to work scheme)
• Flexi-TIme
• Commitment to Diversity: We welcome applications from every part of the community and are committed to a truly diverse and inclusive culture. We foster a sense of belonging, welcoming all perspectives and contributions, and providing equal access to opportunities and resources for everyone.
• If you have a disability or need any reasonable adjustments during the application and selection stages please let us know, and we will respond in a way that best fits your needs.

Who We Are:

Leidos UK & EUROPE – we work to make the world safer, healthier, and more efficient through technology, engineering and science.

Leidos is a growing company delivering innovative technology and solutions focused on safeguarding critical capabilities and transformation in frontline services, our work in the United Kingdom includes addressing some of the most complex problems in defence, healthcare, government, safety and security, and transportation.

Pay Range: £61,500.00-£78,800.00

The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.

Leidos Leidos is an industry and technology leader serving government and commercial customers with smarter, more efficient digital and mission innovations. Headquartered in Reston, Virginia, with 47,000 global employees, Leidos reported annual revenues of approximately $17.2 billion for the fiscal year ended January 2, 2026. For more information, visit www.Leidos.com.

Pay and Benefits Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers. Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retirement. More details are available here.

Securing Your Data Leidos will never ask you to provide payment-related information at any part of the employment application process. And Leidos will communicate with you only through emails that are sent from a Leidos.com email address. If you receive an email purporting to be from Leidos that asks for payment-related information or any other personal information, please report the email to [e-mail].

Commitment and Diversity All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.