Zero Trust Security for Modern UK Businesses
Zero trust replaces the outdated 'trust everything inside the network' model with continuous verification of every user, device, and connection — dramatically reducing your attack surface.
What is Zero Trust?
Zero trust is a security framework based on the principle 'never trust, always verify'. Rather than assuming devices inside your network are safe, every access request — regardless of origin — is authenticated, authorised, and continuously validated. Microsoft, NCSC, and NIST all recommend zero trust as the foundational architecture for modern businesses.
Read our full cybersecurity guideThe Problem with Perimeter-Based Security
Traditional security assumed that everything inside the corporate network was trusted. This worked when employees sat in offices, accessed on-premises servers, and threats came exclusively from outside. That world no longer exists.
Stolen or compromised credentials were the initial attack vector in 22% of data breaches in 2024 — the single largest cause of breaches, surpassing phishing (16%) and software vulnerabilities (Verizon DBIR 2025). (ITPro)
Phishing-resistant, passwordless authentication grew 63% in one year, rising from 8.6% to 14.0% of authentication events (Okta, 2025). (Okta)
Legacy authentication left enabled "just for that one app" — despite being the vector for 99%+ of password spray attacks (Thehackernews)
Today, your data lives in Microsoft 365, Azure, SaaS applications, and on employee devices that travel between home, office, and coffee shops. A VPN and a firewall are no longer sufficient to protect this distributed environment. Once an attacker compromises a single user's credentials — through phishing, credential stuffing, or social engineering — perimeter security offers no resistance to lateral movement.
The Zero Trust Pillars
The NCSC's zero trust architecture guidance identifies six pillars that together create a comprehensive framework:
- Identity — Verify every user with strong authentication (MFA, passwordless) and behavioural analytics
- Devices — Only allow managed, compliant devices to access corporate resources
- Applications — Control access at the application layer, not just the network
- Data — Classify and protect data regardless of where it's stored or how it's shared
- Infrastructure — Continuously assess infrastructure health and apply least-privilege access
- Networks — Microsegment networks and encrypt all traffic, including east-west
Implementing Zero Trust with Microsoft 365
For most UK SMEs, Microsoft 365 Business Premium provides the ideal zero trust foundation. Conditional Access policies enforce MFA and device compliance. Microsoft Entra ID (formerly Azure AD) manages identity. Microsoft Defender for Business handles endpoint protection. Intune manages device configuration and compliance. Together, these tools implement zero trust without requiring specialist hardware or complex on-premises infrastructure.
Zero Trust Capabilities AMVIA Deploys
We implement all six zero trust pillars using Microsoft's cloud-native security stack, configured and monitored by our certified engineers.
Passwordless Authentication
Deploy Windows Hello for Business, FIDO2 keys, or Microsoft Authenticator to eliminate password-based attack vectors entirely.
Conditional Access Policies
Enforce access rules based on user risk, device compliance, location, and application sensitivity — blocking suspicious sign-ins automatically.
Device Compliance Enforcement
Intune MDM ensures only compliant, managed devices can access corporate data. Non-compliant or personal devices are limited to approved resources only.
Data Classification & DLP
Microsoft Purview automatically classifies sensitive data and enforces policies preventing exfiltration via email, USB, or cloud uploads.
Zero Trust Implementation Checklist
Key milestones for a zero trust migration — use this to track your readiness or share with your IT provider.
MFA enforced for all users
Including shared mailboxes, service accounts, and admin accounts.
Conditional Access policies active
At minimum: block legacy authentication and require compliant devices for sensitive apps.
Device management deployed
All corporate devices enrolled in Microsoft Intune with compliance policies applied.
Privileged Identity Management enabled
Admin roles require just-in-time elevation with approval workflow and audit logging.
Data classification labels applied
Sensitivity labels on emails and documents; DLP policies active in M365.
Network segmentation reviewed
Internal network segmented; East-West traffic monitored; VPN replaced or supplemented with ZTNA.
Zero Trust FAQs
Yes — in fact, cloud-first SMEs are often better positioned to adopt zero trust than large enterprises with legacy infrastructure. Microsoft 365 Business Premium includes most of the tools needed to implement a strong zero trust posture. AMVIA can typically deploy a baseline zero trust configuration for a 50-person business within two to four weeks.
Not necessarily. In the short term, zero trust network access (ZTNA) can coexist with a VPN. However, many businesses do eventually replace their VPN with ZTNA solutions such as Microsoft Entra Private Access, which provide application-level access controls rather than blanket network access. We advise a phased transition rather than a hard cutover.
Zero trust is specifically designed for distributed work patterns. Unlike perimeter security, it doesn't matter whether a user is in the office, at home, or in a coffee shop — every access request is verified the same way. This eliminates the security gap that hybrid working creates in traditional network architectures.
Ready to Modernise Your Security Architecture?
Our Microsoft-certified engineers will assess your current environment and design a pragmatic zero trust roadmap tailored to your business size and risk profile.
Related Guides
The Complete Guide to Cybersecurity for UK SMEs
A comprehensive overview of cyber threats, protective controls, and compliance frameworks for UK businesses.
What is Cyber Essentials Plus?
How CE+ relates to zero trust principles and why achieving certification is the right first step for most SMEs.
Microsoft 365 Business Premium vs E5
Comparing the zero trust capabilities included in each licence tier to find the right fit for your business.