What is a Fractional CISO? Understanding the Role
The fractional CISO meaning centres on flexible, senior-level cybersecurity leadership. Unlike traditional full-time CISOs earning £150,000-£250,000 annually, a part-time security executive works with multiple companies simultaneously, bringing diverse security experience across industries and compliance frameworks.
UK Market Context: As the BBC reports on the evolving UK job market (Jan 2026), companies are increasingly embracing flexible executive arrangements. Fractional CISOs represent a key part of this shift, part of the broader fractional work trend transforming cybersecurity leadership.
With increasing cyber threats, regulatory requirements (GDPR, SOC 2, ISO 27001), and customer security questionnaires, companies need senior security leadership but often cannot justify or afford a full-time CISO. The fractional model provides enterprise-grade security expertise at a fraction of the cost.
Key Responsibilities
A fractional CISO performs the same functions as a full-time Chief Information Security Officer, but on a part-time basis:
Security Strategy
Developing comprehensive cybersecurity roadmaps and risk frameworks
Compliance
Achieving and maintaining SOC 2, ISO 27001, GDPR, HIPAA compliance
Risk Assessment
Identifying vulnerabilities and managing security risks
Incident Response
Building and testing security incident response procedures
Vendor Management
Evaluating security tools, managing security vendors
Team Building
Hiring and mentoring security teams, managing MSSPs
Fractional vs Interim vs Full-Time CISO: How They Compare
Understanding the difference between a fractional CISO, interim CISO, and full-time CISO helps companies choose the right security leadership model:
| Factor | Fractional CISO | Interim CISO | Full-Time CISO |
|---|---|---|---|
| Commitment | 1-3 days/week | Full-time (temp) | Full-time (perm) |
| Duration | Ongoing (6+ months) | 3-9 months typical | Permanent |
| Monthly Cost | £4,000-£12,000 | £18,000-£28,000 | £15,000-£25,000+ |
| Annual Cost | £48,000-£144,000 | £54,000-£84,000 (3mo) | £180,000-£300,000+ |
| Primary Focus | Strategy, compliance, governance | CISO gap, crisis, transformation | Full security ownership |
| Flexibility | Scale up/down easily | Fixed contract term | Limited flexibility |
| Best For | SMEs, startups, Series A-C | CISO vacancy, incident, M&A | Large enterprises, regulated |
Cost Comparison: A fractional CISO at 2 days/week costs £96,000-£144,000/year vs £180,000-£300,000+ for a full-time CISO (including salary, NI, pension, benefits, and recruitment fees). That's 50-70% savings while maintaining enterprise-grade security leadership.
When to Hire
- SOC 2 certification: When pursuing SOC 2 Type I or Type II compliance
- Enterprise sales: When large customers require security questionnaires and audits
- Post-funding: After raising Series A/B when security expectations increase
- Data protection: Handling sensitive customer data (PII, health, financial)
- Board requirements: When board or investors require security oversight
- Incident preparation: Building incident response capabilities before a breach occurs
UK Cost Guide
Fractional CISO costs in the UK typically range from £1,000-£1,800 per day based on experience and sector:
- • 1 day per week (4 days/month)
- • Security policy development
- • Compliance guidance
- • Vendor security reviews
- • 2 days per week (8 days/month)
- • SOC 2 / ISO 27001 prep
- • Security architecture
- • Incident response planning
- • Security awareness training
- • 3+ days per week
- • Full CISO responsibilities
- • Board-level reporting
- • Security team management
- • M&A security due diligence
Why security leadership matters now
The average cost of a data breach in the UK is over £3.4 million (IBM Cost of Data Breach Report 2025). A fractional CISO helps prevent breaches and ensures compliance at a fraction of the cost of both a full-time hire and a potential incident.
Fractional CISO Hourly Rates UK
For ad-hoc consultations and project-based security work:
| Level / Specialisation | Hourly Rate | Best For |
|---|---|---|
| Standard Fractional CISO | £150-£200/hour | Policy reviews, security assessments |
| Senior CISO (15+ years) | £200-£275/hour | Board reporting, M&A due diligence |
| FinTech / Regulated Specialist | £225-£325/hour | FCA compliance, PCI-DSS |
| Incident Response Expert | £250-£400/hour | Breach response, forensics |
Professional Bodies & Certifications
Key qualifications that validate fractional CISO expertise:
(ISC)² - CISSP
Certified Information Systems Security Professional
Gold standard certification
ISACA - CISM
Certified Information Security Manager
Management-focused certification
NCSC
UK National Cyber Security Centre
Government security guidance
CREST
Security testing accreditation
Penetration testing standards
