Can MDR replace SIEM entirely for a UK SME?

For most SMEs, yes. MDR delivers the detection and response outcomes that SIEM promises but requires dedicated analysts to achieve. MDR providers use their own log correlation and threat intelligence platforms, eliminating the need for a separate SIEM investment. With 43% of UK businesses experiencing a breach or attack (DSIT 2025), the priority should be effective response capability, which MDR delivers out of the box.

Why is SIEM so expensive compared to MDR for small businesses?

SIEM is a platform, not a service — it requires skilled analysts to write detection rules, tune alerts, and investigate findings. A SIEM licence alone can cost £5,000 to £50,000 per year, and staffing analysts adds £45,000 to £65,000 per person annually. MDR bundles the technology and the expertise into a single per-endpoint fee, typically costing £10,000 to £30,000 per year total for an SME.

Does MDR include any log collection and correlation like SIEM?

Yes. MDR providers collect telemetry from endpoints, cloud services, and identity platforms, then correlate this data to identify threats. The difference is that MDR also acts on what it finds — triaging alerts, investigating anomalies, and containing threats. SIEM stops at detection and alerting, leaving your team responsible for the response. For the 85% of breaches involving phishing (DSIT 2025), rapid response is what limits damage.

When should a business choose SIEM over MDR?

SIEM makes sense when you already have a security operations team, need to meet specific regulatory log retention requirements, or require deep forensic analysis across diverse data sources. If you have three or more security analysts who can operate the platform around the clock, SIEM provides powerful customisation. Otherwise, MDR delivers superior outcomes at a fraction of the total cost.

MDR vs SIEM: What's the Difference for UK Businesses?

SIEM collects and analyses security logs. MDR provides continuous monitoring with human-led response. For most UK SMEs, MDR delivers better outcomes at lower total cost than SIEM.

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Key Facts

£3,550average cost of the most disruptive breach for UK businesses

43%of UK businesses experienced a cyber breach in 2025 (DSIT)

99.99%of compromised accounts had not enabled MFA (Microsoft)

49%of UK businesses have a basic cyber security skills gap (DSIT)

Last updated: March 2026

MDR vs SIEM: Feature Comparison

Feature	MDR£8–£25/endpoint/moRecommended	SIEM£5,000–£50,000+/year
Threat detection
Log collection and correlation	Included
24/7 human monitoring
Incident response
Requires security analysts to operate	No	Yes
Total cost for 100-person business	£800–£2,500/mo	£6,000–£12,000/mo (platform + staff)

When to Choose Each Option

Choose MDR if...

You need effective threat detection and response without hiring security analysts. MDR gives you the complete service — detection, investigation, and response — at a fraction of SIEM-plus-staff costs.

Choose SIEM if...

You have an existing security team, need to meet specific log retention requirements, or require deep correlation across diverse data sources. SIEM is a powerful tool — but only when operated by skilled analysts.

Cost-Benefit Analysis

SIEM platform costs plus the salary of one or more security analysts (£45,000–£65,000 each) typically exceeds £80,000–£120,000/year for a UK SME. MDR provides equivalent or better threat detection and response for £10,000–£30,000/year. For businesses without an existing security team, MDR is the clear winner on both effectiveness and cost.

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The AMVIA Recommendation

For UK SMEs without a dedicated security operations team, MDR is the right choice over standalone SIEM. MDR delivers the monitoring and response outcomes that SIEM promises but requires significant in-house expertise to realise. Larger organisations with existing SOC teams can benefit from SIEM as a log aggregation and correlation layer — but start with MDR first.

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