Key Steps to Implement ISO 27001

 Implementing ISO/IEC 27001 is the work you do before certification. It means setting up an Information Security Management System (ISMS) and running it day-to-day. Certification comes later, when an independent certification body audits that system. The steps below follow the sequence most UK organisations use to implement ISO 27001 in a practical, evidence-led way. 

Understand what ISO/IEC 27001 requires and secure leadership commitment before you start detailed work. The standard expects an ISMS: a system for managing information security risks through policies, controls, audits, and continual improvement.

Leadership should agree priorities, resources, and who makes decisions for the ISMS, not just sign off on a policy. This matters because many implementation projects fail when ownership is unclear, security is treated as “just IT work”, or there is no time set aside for risk assessment, internal audit, and fixing gaps before certification.

Define a clear ISMS scope that sets out what is included: services, systems, locations, data, and key suppliers. A focused scope is faster to implement and easier to evidence than a broad “whole business” scope at the start.

Keep the scope specific and avoid vague statements like “all IT”. Also avoid excluding critical systems or suppliers that affect security outcomes. Your scope becomes the boundary for risk assessment, control selection, and evidence, and it is what a certification body will audit when you later move to ISO 27001 certification.

Establish the ISMS foundations so it can run in a consistent way. Assign roles (such as ISMS owner, risk owners, and control owners), set information security objectives, and agree how decisions and exceptions are handled.

Put simple document control in place so policies and procedures are approved, versioned, and easy to find. The aim is a working management system with clear ownership and repeatable ways of working, not a large library of documents that nobody uses or understands.

Identify information security risks for the ISMS scope, carry out a simple risk assessment, and record the results in a structured way. Focus on realistic threats, weaknesses, and impacts in business terms, such as downtime, data loss, fraud, or contractual damage.

Score risks using clear criteria, assign owners, and note current controls and gaps. This step matters because ISO 27001 is risk-based. Your choice of controls should link back to assessed risks, and auditors will expect to see that link in the risk assessment and in how you explain your control set.

Select controls to treat your risks and create a risk treatment plan. ISO/IEC 27001 includes Annex A, a reference set of controls covering access management, supplier security, logging, incident response, and more.

Your risk treatment plan should state how each significant risk will be handled, which controls apply, who owns delivery, and target dates. Then complete the Statement of Applicability (SoA). The SoA lists Annex A controls, shows which are applicable for your ISMS scope, and explains any exclusions.

Implement the controls and the operating procedures that keep them running. Focus on what matters most for your scope, such as access control, backups, change management, incident response, supplier checks, and logging.

For each control, set out how it works, who performs it, where records are kept, and what evidence exists (for example, access reviews, change records, logs, and approvals). Implementation is pre-certification work: by this stage you should be able to show the ISMS operating in real life, with consistent, usable evidence.

Train staff so people understand their responsibilities under the ISMS. Provide general awareness training for everyone in scope, then role-based training for higher risk roles such as administrators, developers, and service owners.

Keep the content practical. Focus on handling sensitive data, using access controls correctly, reporting incidents, and following core procedures. Record who has completed training and when refreshers are due. Auditors will look for evidence that people understand and follow the rules, not just that policy documents exist on a shared drive.

Conduct an internal audit and management review to confirm the ISMS is operating and ready for certification. Internal audit checks whether ISO/IEC 27001 requirements and your own ISMS processes are being followed, using sampled evidence rather than policy statements.

Management review is leadership’s formal check of ISMS performance, including risks, incidents, audit results, and improvement actions. Together, these activities show governance and continual improvement in action. They usually highlight the final gaps to fix before external audits.

1. Secure leadership commitment and agree objectives for the ISMS.
2. Define a clear ISMS scope (services, systems, locations, data, suppliers).
3. Establish the ISMS (roles, governance, policies, document control).
4. Identify and assess information security risks in business terms.
5. Select controls, create a risk treatment plan, and complete the SoA for Annex A.
6. Implement controls so they run in practice and generate usable evidence.
7. Train staff, keep it practical, and record completion and refreshers.
8. Run internal audit and management review before seeking certification.