Written by Paul Brown | Last updated 17.11.2025 | 19 minute read
Zero-trust security has moved from a buzzword to a strategic necessity for UK public sector technology. As government departments digitise services, embrace cloud platforms and share more data across organisational boundaries, traditional perimeter-based security models are no longer enough. Attackers are more sophisticated, supply chains are more complex, and citizens expect frictionless yet secure access to services. In this context, implementing zero-trust security across Government platforms is not simply an IT upgrade; it is a wholesale shift in how the public sector thinks about identity, access, data and trust itself.
This article explores how zero trust fits into the evolution of GovTech in the UK, and offers a practical roadmap for designing, building and operating government platforms that treat every identity, device and connection as untrusted by default. It focuses particularly on multi-tenant, cross-department platforms, such as those supporting shared services, citizen-facing portals and API ecosystems between central and local government.
Over the last decade, UK public sector technology has been reshaped by three converging trends: cloud adoption, platform consolidation and the drive for joined-up digital services. Departments, agencies and local authorities are gradually moving away from monolithic, siloed systems and towards shared platforms for identity, payments, case management and data exchange. This platformisation allows the state to act more like an ecosystem, where services can be composed, reused and integrated with greater speed and lower cost.
However, this same consolidation amplifies cyber risk. When more services sit on common infrastructure, the blast radius of a breach increases dramatically. A compromise in one tenant, integration or supplier can become a stepping stone to far more sensitive systems and datasets. This is where zero trust becomes central rather than optional. Rather than assuming that anything inside a “government network” can be trusted, zero trust starts from the assumption that networks are already compromised, and that trust must be earned continuously, transaction by transaction.
For UK GovTech leaders, zero trust is also a tool for aligning cybersecurity with political and policy imperatives. Citizens are being asked to share more data and to rely on digital-first services for benefits, healthcare and justice. Public confidence depends on visible, defensible security measures and clear assurances that data sharing is tightly controlled. Zero trust, if implemented thoughtfully, can provide a narrative that is both technically robust and understandable: no blanket trust, no implicit access, and continuous protection based on who you are, what you’re doing and the risk of that action.
There is also a strategic workforce dimension. Public sector organisations are increasingly adopting hybrid and remote working, relying on SaaS tools and multi-cloud environments. The old model of pulling staff “back into the secure network” simply does not map to this reality. Zero trust offers a way to secure access wherever people work, on whatever device they are using, without forcing all traffic through brittle VPNs or legacy gateways that introduce latency and operational overhead.
Finally, zero trust dovetails with the UK’s broader goals for data-driven government. By focusing on identity, authorisation and context, rather than static network zones, it becomes easier to expose APIs securely between departments, create data products and adopt event-driven architectures in a controlled way. This helps unlock reuse of data and platforms while maintaining the granularity of control demanded by regulations and public expectation.
Implementing zero trust in the public sector is less about buying a specific product and more about operationalising a set of security principles across architecture, governance and delivery. Governments already work within stringent oversight and accountability frameworks; zero trust should reinforce those rather than conflict with them. At its heart, the model rests on three intertwined ideas: never trust by default, always verify, and assume breach.
The first principle, “never trust by default”, requires a shift away from network locations or organisational boundaries as proxies for trust. Being on a “gov.uk” network segment or within a department’s VPN can no longer be treated as sufficient. Instead, trust is evaluated at the level of identity (human and machine), device posture, and the specific resource being accessed. For example, a civil servant accessing a low-risk knowledge base from a managed laptop may require minimal friction, while access to a sensitive case management system should demand stronger verification, tighter monitoring and stricter constraints on what can be done.
The second principle, “always verify”, means authentication and authorisation are continuous processes, not one-off gates. Users might authenticate strongly at the start of a session, but their access needs to be continuously re-evaluated as their context changes — their location, device health, network, behaviour and the sensitivity of what they are doing. This calls for adaptive, risk-based access controls that can step up verification when signals look suspicious, rather than passively trusting a long-lived session token or VPN tunnel.
The third principle, “assume breach”, pushes government teams to design platforms as if an attacker already has a foothold somewhere in the environment. This changes priorities: lateral movement, privilege escalation and data exfiltration become more important threats to plan for than the initial compromise. It encourages the use of granular segmentation, least-privilege access, strong logging, and automated detection and response. It also reinforces the need for clear blast-radius boundaries — so that even if one workload, account or supplier is compromised, the damage can be contained and investigated.
In the context of UK GovTech, these principles need to be translated into patterns and standards that can work across diverse environments — from on-premise legacy systems and private data centres to multi-cloud estates, SaaS platforms and edge devices in frontline services. Zero trust must be articulated in terms that contract managers, policy leads and service owners can understand, not only security architects. That means clear expectations for identity federation, logging, supplier obligations and data classification, rather than black-box security edicts.
For shared government platforms, a zero-trust architecture has to deal with multi-tenancy, cross-organisational integration and varying levels of digital maturity across departments and local authorities. A practical approach is to treat the platform as a collection of composable security capabilities, rather than a single monolithic stack, and to design for different levels of adoption and integration.
At the centre of this architecture sits identity, both for people and for workloads. A strong, standards-based identity layer allows multiple government bodies to federate their own directories, bring their own identity providers where appropriate, and still benefit from consistent, policy-driven access control at the platform layer. Supporting open protocols for authentication and authorisation, and designing around a single source of truth for identity attributes, allows services to make fine-grained access decisions without duplicating identity logic in each application.
Around this identity core, the platform should provide a policy decision and enforcement layer. This is where zero trust becomes programmable: access policies can be defined centrally, expressed as code, and pushed out consistently across microservices, APIs, gateways and data stores. Policy-as-code helps ensure that every service on the platform interprets access rules consistently, while still allowing tenant-specific variations where justified. It also makes it easier to audit, test and evolve policies as regulations, threats and service designs change.
Network architecture needs to evolve from static segmentation to micro-segmentation and application-level controls. Rather than granting broad access to a “platform network”, you define small, tightly scoped trust zones around specific services or data sets. Service-to-service communication is authenticated and authorised using mutual TLS, strong service identities and explicit allow-lists. This constrains lateral movement and ensures that even if one service is compromised, it is difficult for an attacker to pivot to others without triggering alerts.
Data security is another core design pillar. A zero-trust architecture for GovTech platforms must be explicit about which datasets are held centrally, how they are classified, and how access is governed. Encryption at rest and in transit is necessary but not sufficient; access controls, tokenisation or pseudonymisation, and clear data lineage are just as critical. Fine-grained access models allow a service to read only the fields it requires, ideally via well-governed APIs, instead of direct access to entire databases. This minimises the impact if credentials or tokens are leaked.
Finally, observability and security analytics need to be treated as first-class architectural concerns. Zero trust produces a large volume of authentication events, policy decisions, network telemetry and application logs. If this data is not collected, correlated and analysed, the model cannot deliver on its promise of continuous verification and rapid incident detection. Designing log schemas, retention policies and access patterns up front, and integrating them with security operations, is essential to avoid blind spots and unmanageable noise.
Moving from high-level principles to practical implementation is often where government organisations struggle. Legacy systems, complex procurement frameworks and a mix of in-house and outsourced delivery models can create resistance and fragmentation. A structured, incremental approach helps turn zero trust from an abstract strategy into a sequence of achievable changes, each delivering tangible risk reduction.
A useful starting point is to define a clear scope. Rather than attempting to “do zero trust” across an entire department, focus initially on a specific platform or cluster of services, such as a shared case management platform, a citizen-facing portal, or an internal data-sharing hub. Within that scope, map out users, devices, applications, APIs, data flows and suppliers. This mapping exercise should reveal where implicit trust currently exists — for example, shared admin accounts, flat networks, overly broad firewall rules or unmanaged third-party integrations.
With this visibility, you can prioritise foundational capabilities that underpin zero trust. These often include:
Once these foundations are in place, you can move into more targeted zero-trust patterns. Common examples in government platforms include:
It is equally important to address the software delivery pipeline. Zero trust is undermined if code is deployed by opaque processes, if secrets are hard-coded, or if infrastructure is configured manually and inconsistently. Adopting infrastructure-as-code, secret management, and automated policy enforcement in CI/CD pipelines allows security to be baked into delivery rather than bolted on. For example, a platform could enforce that any new service must register its identity, declare its dependencies, and define its access policies before deployment.
Change management and communication are often underestimated. Civil servants, frontline staff and suppliers need to understand why zero trust is being implemented and what it means for their day-to-day work. Framing changes in terms of user benefits — such as simpler access from different devices, fewer VPN hassles, and faster incident resolution — can help build buy-in. Engaging unions, staff networks and local authorities early, especially when changes affect remote working or bring-your-own-device arrangements, is vital to avoid surprises and resistance.
Finally, governance needs to be aligned with implementation. Zero trust introduces new questions about who owns access policies, how exceptions are managed, and how disputes between security teams and service owners are resolved. Clear decision-making structures, risk acceptance processes and escalation routes ensure that the model remains workable and does not become a rigid barrier to service improvement. This governance should be codified but also reviewed regularly, as both the technology landscape and threat environment evolve.
Identity is the beating heart of zero-trust security in UK government platforms. But identity in the public sector is multifaceted: you have staff identities, contractor and supplier identities, service accounts, API clients, machine identities, and citizen or business identities consuming services. Implementing zero trust across platforms requires a coherent strategy that can span these categories without collapsing them into a single, oversimplified model.
For staff and administrative users, a robust directory and single sign-on capability provide a baseline. Multi-factor authentication should be standard for high-value platforms, especially for privileged accounts. Conditional access – taking into account device status, location, and the sensitivity of the resource – allows the platform to step up security where needed without imposing a uniform burden on all activities. In practice, this might mean that accessing general intranet content from a known, managed laptop requires little friction, while accessing production management consoles demands strong authentication, device health checks and short-lived session tokens.
Machine and service identities need equal attention. In many legacy deployments, service accounts are long-lived, shared and granted broad privileges, making them attractive targets for attackers. In a zero-trust architecture, services authenticate to each other using strongly bound identities, such as certificates or short-lived tokens issued by a central identity provider. These identities should be rotated frequently and tightly scoped, with fine-grained permissions defined via policy-as-code rather than embedded in configuration files. This improves both security and operational manageability.
Citizens and businesses interacting with government platforms require a different balance between security and usability. Friction must be minimised, yet the consequences of account takeover can be severe, especially for services dealing with benefits, tax or immigration. Here, zero trust can enable adaptive security: low-risk interactions might rely on streamlined login flows, while higher-risk actions — such as changing bank details, accessing sensitive records or delegating authority — trigger stronger verification. Government platforms can also make greater use of step-up authentication methods that are accessible and inclusive, avoiding reliance on any single factor that may exclude particular user groups.
Data protection is closely tied to identity in a zero-trust world. The platform must know not only who is asking for data, but also what data they need, for what purpose, and under which legal basis. Implementing attribute-based access control (ABAC) can help bridge the gap between policy and implementation. Rather than encoding roles and entitlements in each application, you define access rules based on attributes such as user role, department, case status, data classification and purpose of use. These rules can then be evaluated centrally at run-time for each request, providing both flexibility and a clear trail for auditing.
Continuous assurance is the final piece of the puzzle. Zero trust assumes that things go wrong and that compromises can occur despite best efforts. Therefore, platforms need strong monitoring, anomaly detection and incident response capabilities. Telemetry should be collected from endpoints, identity systems, network controls and applications, and then correlated to detect unusual patterns: repeated failed logins, access from unexpected locations, sudden spikes in data access, or deviations from known behavioural baselines. Automated playbooks can respond quickly to suspected incidents, revoking tokens, isolating devices or restricting access while investigations are underway.
To sustain this over time, government platforms should embed security metrics and feedback loops into their governance. Instead of focusing solely on compliance checklists, they can track indicators such as mean time to detect and contain incidents, coverage of multi-factor authentication, proportion of services using mutual TLS, or number of high-risk exceptions in access policies. These metrics help leaders understand whether zero trust is working in practice and where further investment or simplification is needed.
No UK government platform exists in isolation. Third-party suppliers, legacy systems and local authorities are integral to how services are designed, built and operated. A credible zero-trust strategy must therefore extend beyond the immediate boundaries of a single department or platform and create a broader ecosystem of controlled, auditable trust.
Suppliers are often granted significant access to government systems for development, support or integration purposes. Historically, this has sometimes meant persistent VPN connections, shared accounts or opaque remote access tools. In a zero-trust environment, supplier access should be governed by the same identity and policy controls as internal staff, if not more stringent. Suppliers should authenticate via dedicated identities, ideally federating from their own corporate directories rather than using ad-hoc accounts, and their access should be time-bounded, least-privilege and fully logged.
Contracting and procurement play a vital part here. Zero trust cannot be retrofitted effectively if contracts do not require suppliers to support modern security controls, provide logs, or adhere to specific identity and access management patterns. Framework agreements and statements of work should include clear technical and governance expectations, including adherence to agreed standards for encryption, logging, patching, vulnerability disclosure and incident reporting. This turns zero trust from an internal aspiration into a tangible set of requirements that shape market behaviour.
Legacy systems are another challenge. Many critical public services depend on older applications that were not designed with zero trust in mind, often running on ageing infrastructure with limited vendor support. Replacing these systems outright can be costly and disruptive, yet leaving them untouched creates significant risk. A pragmatic approach is to place strong, modern controls around legacy systems, treating them as “high-risk enclaves” within the broader architecture. Access can be mediated via identity-aware gateways, and connectivity restricted to only those services that genuinely need it, with detailed monitoring of all interactions.
In parallel, modernisation roadmaps can prioritise refactoring or replacement of those legacy components that present the greatest risk or block adoption of platform-wide controls. For instance, an old system that requires broad, uncontrolled database access may be wrapped in an API layer that exposes only necessary operations, with the underlying database placed behind stronger segmentation and monitoring. Over time, as new capabilities are developed, services can be migrated away from the legacy core without attempting a risky “big bang” cutover.
Local authorities and arms-length bodies add another layer of complexity. They often have their own IT estates, procurement processes and digital strategies, yet increasingly consume or contribute to shared central platforms. A zero-trust ecosystem needs to respect this autonomy while still enforcing baseline controls. One approach is to define “onboarding tiers” for organisations connecting to a central platform, each with clearly articulated technical and governance requirements. For example:
This tiered model allows central government to set minimum expectations while giving local bodies a realistic path for incremental improvement, rather than an all-or-nothing mandate.
Finally, collaboration and knowledge sharing are crucial to making zero trust real across such a diverse landscape. Communities of practice, cross-government reference architectures, reusable code libraries and shared security services can dramatically reduce duplication and inconsistency. By publishing patterns and blueprints that are battle-tested in one department and reusable in others, government can accelerate adoption and avoid each organisation reinventing its own version of zero trust in isolation.
Technology and architecture are only half the story. For zero trust to succeed in UK GovTech, it has to become part of how teams think, how projects are run, and how leaders make trade-offs between risk, cost and user experience. This requires sustained effort to shift culture, skills and incentives across the public sector.
One key cultural change is moving from point-in-time compliance to continuous risk management. Traditional government assurance processes often revolve around a major security assessment before go-live, followed by lengthy review cycles. Zero trust demands more frequent, lightweight checks embedded in delivery pipelines and operations. Security teams need to be partners in delivery, not gatekeepers who appear only at the end. Adopting security champions within multidisciplinary teams, and giving them access to reusable patterns and tools, can help bridge the gap between central security functions and frontline delivery units.
Skills development is another priority. Zero trust spans multiple domains — identity, networking, application security, data governance, incident response — and requires people who can navigate the intersections. Investment in training, mentoring and career pathways for cyber professionals inside government will pay dividends, particularly if it is coupled with opportunities to work on high-impact, high-visibility platforms. At the same time, non-specialists such as product managers, service designers and policy leads need enough literacy to make informed decisions about security trade-offs and to spot when requirements may be drifting away from the zero-trust model.
Leadership support is essential. Senior civil servants and ministers should understand, at a strategic level, what zero trust means and why some initiatives may initially introduce more friction or cost in order to reduce long-term risk. Clear, consistent messaging from the top can empower teams to prioritise security controls even when under pressure to deliver features quickly. Conversely, if leadership treats cyber security as a box-ticking exercise, zero trust risks becoming diluted into superficial branding.
Measurement and storytelling can help maintain momentum. Collecting evidence of improved security posture — such as detected and contained intrusions, reduced attack surface, or faster response times — makes the benefits of zero trust tangible. Equally, sharing stories about near-misses or real incidents, handled effectively thanks to strong identity controls or segmentation, can reinforce the value of the approach. This kind of narrative, combined with transparent incident reporting and lessons learned, builds trust both within government and with citizens.
Finally, zero trust should be framed not as a destination but as a continuous journey. Threats evolve, technologies change, and public expectations shift. What counts as a robust control today may be insufficient tomorrow. Embedding mechanisms for learning and adaptation — regular architecture reviews, red-teaming exercises, simulated incidents and cross-organisational retrospectives — will ensure that the zero-trust model remains alive and responsive rather than ossified into a rigid doctrine.
In summary, implementing zero-trust security across UK government platforms is a complex but achievable endeavour. It demands a clear understanding of the strategic context of GovTech modernisation, a principled yet pragmatic architectural approach, and a relentless focus on identity, data protection and continuous assurance. It also requires integrating suppliers, legacy systems and diverse public sector bodies into a coherent ecosystem of controlled trust, and fostering a culture where security is everyone’s responsibility.
Done well, zero trust will not only reduce the likelihood and impact of cyber incidents; it will enable bolder, more joined-up digital services that citizens can rely on with confidence. As the UK continues to modernise its public sector technology, zero trust offers a way to reconcile ambition with assurance — making government platforms resilient, adaptable and worthy of the trust that the public places in them every day.
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