Aerial view of Portsmouth Harbour and Navy Dockyard from the Spinnaker Tower

mission-critical secure network

From secure network infrastructure and structured cabling through to operational support and technology refresh programmes, Onnec provides trusted delivery services for organisations where security, assurance and operational resilience are paramount.

Male Engineer Hands Connecting Fiber Optic Cable Into Server Rack Patch Panel
Military, control room and man on computer in office, data center and monitor for technical support, cybersecurity or surveillance. Army, officer or work in tech, security or government communication

trusted delivery insecure environments

Defence and secure-government organisations operate in some of the most demanding and highly regulated environments in the UK. Success requires a partner that understands not only secure infrastructure solutions, but also security culture, governance, assurance and operational delivery.

Onnec combines 40 years of infrastructure expertise with a dedicated MOD & Secure Services capability, enabling customers to deploy and operate secure IT infrastructure with confidence.

Our teams support projects ranging from estate modernisation and secure network deployments through to data centre infrastructure, technology refresh programmes and operational support services.

When infrastructure is mission-critical, there is no room for compromise. Security, resilience, governance and safety must underpin reliable defence infrastructure across restricted, complex environments and evolving technologies.

our solutions & services

When you work with us, you get expert engineers and dedicated support to deliver certainty in your IT infrastructure.

Structured cabling

structured cabling

The backbone of your infrastructure, built to the highest standard. Our expert team installs structured cabling that ensures certainty in every connected space.

Data centre hall

defence DATA CENTRES

Supporting mission-critical infrastructure through secure installations, including equipment installation, integration, and deployment within controlled environments.

smart networked connected city

network solutions

Securely connect people, spaces and devices with our end-to-end services, from fibre optic infrastructure and multi-site connectivity to secure infrastructure assurance and testing.

man in data centre support services

support services

The right experts at the right time, delivering tailored managed services that keep your defence IT infrastructure secure, available and performing at its best.

Formation of 4 RAF Typhoons

Supporting defence and security-critical organisations

Whether supporting a defence estate, secure government environment or another security-critical organisation, Onnec provides the secure infrastructure solutions, expertise and disciplined delivery needed to operate with confidence.

A trusted infrastructure partner for secure environments.

Want to get in touch?

Our MOD & Secure Services division is led by experienced professionals with decades of experience delivering secure network infrastructure, telecommunications and critical technology programmes across defence and government estates. Whether you are undertaking estate modernisation, network transformation, data centre expansion or technology refresh programmes, Onnec provides the expertise, governance and trusted delivery capability required to succeed in secure environments.

October 20th 2026: today we announced that we have agreed to be acquired by CBRE Group, Inc., a global leader in commercial real estate services and investment, subject to regulatory approvals.