What is Non-Functional Requirements? — UK Software Development Guide

4 min readJune 2025ClickMasters Technical TeamReviewed by James Whitmore, CTO
what are non-functional requirements

Direct Answer

Non-functional requirements (NFRs) describe how a system should perform, rather than what it should do. They include: performance (response time, throughput), security (encryption, access control), availability (uptime, disaster recovery), scalability (handling increased load), maintainability (ease of making changes), and compliance (UK GDPR, Cyber Essentials, WCAG 2.1).

Non-functional-requirements in the UK

Non-functional requirements have specific UK regulatory dimensions that are often missed in software projects. UK GDPR compliance requirements are NFRs (encryption, audit logging, right to erasure). WCAG 2.1 AA accessibility is an NFR (legally required under PSBAR and Equality Act). Cyber Essentials is a set of NFRs (firewalls, secure configuration, patch management). FCA operational resilience defines NFRs (availability, recovery time). ClickMasters captures all NFRs during Technical Discovery — including UK regulatory NFRs — before development begins. NFRs not captured in Discovery become expensive change requests later.

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