A CISO (chief information security officer) is the senior executive responsible for protecting an organisation's information, systems and data from cyber threats. They set security strategy, manage risk, oversee compliance and incident response, and report security posture to the board in business terms.
What it means
The CISO turns cyber risk into decisions the board can make. Typical responsibilities include risk assessment, security policies, supplier security, staff awareness, incident response planning, certifications such as Cyber Essentials or ISO 27001, and answering security questionnaires from customers and insurers.
A CISO is different from an IT manager. The IT team runs the systems, while the CISO sets the security standards and independently checks they are met.
When you need one
SMEs often bring in a fractional CISO when enterprise customers demand security assurance, a cyber insurer raises questions, the business handles sensitive data, a regulated client requires certification, or after an incident. Leadership Services provides fractional CISOs from its bench of senior directors, from £1,795 per month.
Frequently asked questions
Does a small business need a CISO?
Few SMEs need a full-time CISO, but many need CISO-level thinking, especially if they sell to larger organisations, handle personal or financial data, or operate in regulated sectors. A fractional CISO provides that leadership for a few days a month, alongside the existing IT team or provider.
What is the difference between a CISO and a CIO?
A CIO leads the organisation's technology overall, including systems, suppliers and IT investment. A CISO focuses specifically on security and risk. Keeping them separate provides a degree of independent challenge, so security is not traded off quietly against cost or delivery deadlines.
Learn more
Last updated: 5 November 2026