Penetration Testing UK: 2025 Buyer’s Guide

Who this penetration testing UK guide is for

If you’re a UK-based CTO, Head of Security or IT in a regulated SME to mid-market—fintech, finance, healthcare or SaaS—this is your fast, no-nonsense buyer’s guide to penetration testing UK in 2025. You likely have an audit, a client security questionnaire, or board scrutiny looming, and you need a CREST/CHECK-accredited partner inside 2–4 weeks. Below we demystify costs, scope, deliverables, London lead times, and how to compare penetration testing companies UK so you can purchase with confidence.

Penetration testing UK pricing in 2025

Let’s talk numbers first—because budgets are real and auditors aren’t known for their sense of humour. Pricing for penetration testing UK varies with scope complexity, accreditation, and the level of manual testing. Typical CREST day rates in 2025 range from £900–£1,400 per tester per day (higher for niche expertise, SC-cleared CHECK work or red teamers). Ballpark project ranges you can use for planning:

• External network test: £3,000–£7,000
• Internal network test (onsite/remote): £4,000–£9,000
• Web application test (per app): £4,000–£12,000 (complex auth/workflows push higher)
• API penetration test: £3,500–£8,000
• Mobile app (iOS/Android): £5,000–£12,000
• Cloud configuration review (Azure/AWS/M365/GCP): £5,000–£15,000
• Wireless assessment: £2,000–£5,000
• Social engineering (phishing/vishing): £2,000–£6,000
• Build/configuration review (AD, containers, CI/CD): £2,000–£6,000
• Red team/CBEST/TIBER-UK style: £25,000–£80,000+ depending on scope

Expect 10–25% premiums for expedited slots, out-of-hours work, or when penetration testing London requires short-notice onsite days. If you’re buying penetration testing services UK across multiple assets, request a programme rate—many providers discount multi-scope engagements.

Scoping that fits your audit and risk

Start with outcomes: Which control or requirement are you satisfying? PCI DSS 4.0 11.3? ISO/IEC 27001 (A.8.8), NHS DSPT, or a client MSA? Choosing the right scope for penetration testing UK means stitching together the right mix of tests:

• Perimeter (external): Internet-facing IPs, VPNs, employee portals, SSO, and public SaaS integrations.
• Internal: Simulates a compromised device/insider; privilege escalation, lateral movement, AD hardening.
• Web & API: OWASP Top 10 and business-logic abuse, rate limits, multi-tenant isolation.
• Mobile: Transport security, storage, jailbreak/root detection, API auth.
• Cloud: Azure/AWS/M365 misconfigurations, IAM, conditional access, logging, CIS benchmarks.
• Social engineering: Real-world phishing and vishing to test people, process, and tech.
• Red team: Objective-led simulation across people, process and tech with purple-team learning.

Good scopes for regulated SMEs are pragmatic: test the crown jewels, validate controls, and leave time and budget for remediation and retesting.

Standards and what “good” looks like

The best penetration testing companies UK align to recognised standards and clearly document methodology. Look for:

• CREST certified testers and a CREST member company.
• CHECK for HMG/Government networks; SC clearance as required.
• CBEST/TIBER-UK for financial services threat-led testing.
• OWASP (Web, Mobile, ASVS) and PTES/NCSC informed methods.

Quality deliverables for penetration testing UK should include an executive summary (risk & business impact), technical findings with screenshots and exploit evidence, CVSS scoring, root cause analysis, prioritised remediation, and a formal letter of attestation for auditors—plus one free retest window. If a provider can’t show a sample report, that’s a red flag.

Lead times and availability: penetration testing London vs the rest of the UK

Market demand in the capital is high. Typical lead times for penetration testing London are 2–4 weeks for common scopes (external, web/app/API), extending to 4–8 weeks for red teaming or highly specialised cloud work. Outside London, you’ll often find similar timelines, though onsite constraints can add a week. If you need pen testing UK in a hurry, ask about cancellations or standby slots and be ready with test accounts and whitelisting—speed comes from preparation.

How to compare penetration testing companies UK

Here’s a punchy checklist to separate marketing from mastery when buying penetration testing UK:

• Accreditation: CREST member? CHECK for government work? Confirm tester certifications (CRT, CCT, OSCP, OSWE).
• Sample report: Redacted example showing business impact, evidence, and clear remediation.
• Industry fit: Experience with fintech/healthcare/SaaS controls and auditor expectations.
• Manual depth: How much is manual against business logic vs automated scanning?
• Retesting: At least one free retest within 60–90 days.
• Data handling: UK/EU data residency, secure portals, NDA, ISO 27001 if possible.
• Insurance: Professional indemnity/cyber sufficient for your risk.
• References: Two recent, relevant client references or case studies.
• Team: Who will actually test? Named leads, not only sales engineers.

For more decision tips, see our short read on how to choose pen test, and our broader services guide.

RFP and scoping questions to send today

To accelerate penetration testing UK procurement, copy/paste these into your RFP:

• Objectives and compliance drivers (e.g., PCI 11.3, ISO 27001, client audit).
• Asset inventory: IP ranges, domains, apps/APIs, mobile, cloud tenants.
• Environment: production vs pre-production, data sensitivity and test data availability.
• Auth patterns: SSO/SAML/OIDC, MFA, roles to test, break-glass access.
• Constraints: test windows, rate limits, notifications for disruptive tests.
• Access: VPN or jump-box, source IPs for whitelisting, bastion policies.
• Deliverables: reporting format, remediation workshop, retest scope, attestation letter.
• Security: data handling, storage duration, encryption, UK/EU processing.
• Team: named testers, CREST IDs, experience in your sector.

The clearer your brief, the faster penetration testing services UK can begin.

A typical 2–4 week process

1. Scoping & SOW (T-14 to T-7): Define goals and scope, confirm rules of engagement, schedule access.
2. Kick-off (T-5): Contacts, comms, reporting cadence, emergency procedures.
3. Testing (Days 1–5): Manual-led testing aligned to OWASP/NCSC, daily updates for critical findings.
4. Wash-up (Day 6): Prioritised remediation discussion, evidence review.
5. Report (Day 7–10): Draft review, exec summary, technical appendix, attestation letter.
6. Retest (Within 30–60 days): Validate fixes, final sign-off.

That cadence is common across mature penetration testing companies UK and keeps auditors happy while your engineers stay focused.

How to prepare—and cut a week off your timeline

A little prep goes a long way with penetration testing UK:

• Create test accounts with realistic roles and MFA paths.
• Whitelist tester source IPs, set any required conditional access exceptions.
• Arrange safe test data; mask or snapshots where production is unavoidable.
• Clarify out-of-bounds functions (e.g., payments to live gateways) and provide sandboxes.
• Have backups and monitoring tuned to avoid false alarms.
• Ensure a signed authorisation-to-test letter—no test starts without it.

For a reminder of why all this matters, skim our post on why pen testing.

Common pitfalls to avoid

• Scope too narrow: Only perimeter tested while APIs/mobile/cloud are ignored.
• Report-only mentality: No remediation workshop or retest—auditors ask awkward questions later.
• Automation-heavy: Scans alone miss business logic flaws and chained exploits.
• Bad timing: Testing during major releases or change freezes without coordination.
• No attack narratives: Findings without exploit chains make it hard to prioritise fixes.
• Ignoring people/process: Social engineering reveals gaps tech can’t cover.

FAQs: quick answers for stakeholders

How often should we test?

At least annually, and after major changes. High-risk apps or compliance drivers may justify more frequent pen testing UK.

Is a pen test the same as a vulnerability scan?

No. Scans are automated and breadth-first; penetration testing UK is manual-led, risk-driven, and produces validated, contextual findings.

Do we need CHECK?

Only if you handle HMG/Government networks. Otherwise, CREST-backed penetration testing services UK are widely accepted by auditors.

Will testing cause downtime?

Reputable penetration testing companies UK minimise disruption and coordinate any intrusive tests. Clear rules of engagement are key.

What about cloud and Microsoft 365?

Absolutely in scope. Expect identity and conditional access reviews, privilege design, logging/monitoring and misconfiguration checks as part of penetration testing UK.

Why Arviteni—and how we help you move fast

As a Nottingham-based MSP, we help UK decision-makers source and manage penetration testing UK engagements with vetted CREST and CHECK partners. We’ll refine scope, shortlist providers, fast-track scheduling (often inside two weeks), coordinate access, and translate findings into prioritised fixes—with optional remediation support across Microsoft 365, Azure, networks and endpoints. One point of contact, no fuss.

If you’re ready to shortlist penetration testing companies UK today, drop us a line. We’ll help you choose the right penetration testing services UK, secure a sensible price, and hit your audit deadline—whether you’re in the capital or planning penetration testing London from elsewhere in the UK.