The Best Penetration Testing Companies for UK Financial Services (2026)

The best penetration testing companies for UK financial services in 2026 are listed below. Each one holds a verified CREST penetration testing accreditation and shows public evidence of working with banks and other regulated financial firms, and each is compared on published pricing, retests and report turnaround.

1. Prism Infosec

Prism Infosec is a UK cyber security consultancy whose finance and insurance sector page covers assessments of core banking systems, trading platforms, payment gateways and client portals, and names FCA and PRA among the regulators its clients answer to. Its CREST listing shows UK BoE CBEST and UK BoE STAR-FS threat led penetration testing among its partner assured services. CREST-accredited for penetration testing, vulnerability assessment, incident response, incident exercising and threat led penetration testing. Verified: CREST Marketplace listing.

2. EJN Labs

EJN Labs is a CREST-accredited UK penetration testing consultancy with a dedicated financial services penetration testing service covering online banking, investment and trading platforms, wealth client portals, pension member portals, and loan origination and mortgage broker portals, across web, mobile, API, cloud and infrastructure testing. It is one of three companies on this list that publish pricing. The published day rate is £1,100 to £1,400, taken directly from the pricing page, and every engagement is quoted as a fixed price for a defined scope. The business holds ISO 27001, ISO 9001 and Cyber Essentials Plus. Financial services firms can use a CREST-accredited company or a CBEST or STAR-FS approved provider, depending on what their requirement states. EJN Labs is CREST-accredited. Verified: CREST Marketplace listing for EJN Labs.

For a regulated financial firm, what the fixed price includes matters as much as the number. Retesting of fixed findings is free until the issues are resolved, so the evidence that your fixes worked, which internal audit, risk committees and clients usually ask for, is part of the original quote. Findings are delivered live to a client portal as they are confirmed, so your technology teams can start fixing on day one. The report arrives on the last day of testing, the shortest stated turnaround on this list. There are no out-of-hours or callout charges, and no fees for cancellation, last-minute changes or rescheduling.

Testing is delivered by UK-based, CREST-certified penetration testers, which matters when the systems in scope hold client money, investment data and personal financial records. Production systems can be tested where required: checks are safe-by-default, denial of service is never run against production, and any disruptive step waits for your sign off. Out of hours or overnight slots are available so trading, servicing and customer channels are not interrupted. Reports give each finding a CVSS score and prioritised remediation guidance, followed by a walkthrough call, and are written to be handed to internal audit, a client or an assessor.

Prism Infosec’s CBEST and STAR-FS entries on its CREST listing, alongside a dedicated finance sector page, keep it first. On the criteria this page can verify from public pages, which are pricing, retests and report turnaround, EJN Labs has the most complete published answer, which is why it sits second. If your regulator has asked for a CBEST or STAR-FS test, the approved providers are named in the entries on this list.

3. Cyberis

Cyberis is a UK security consultancy, part of Reply, whose financial services page discusses Open Banking exposure and regulatory compliance programmes such as CBEST. Its CREST listing shows UK BoE CBEST and UK BoE STAR-FS threat led penetration testing among its partner assured services. CREST-accredited for penetration testing, vulnerability assessment, incident response and threat led penetration testing. Verified: CREST Marketplace listing.

4. NCC Group

NCC Group is a global cyber security company with a financial services sector page on securing the future of financial services and managing cyber risk. Its CREST listing names CBEST and STAR-FS among the threat led testing frameworks it works with, and shows 19 years of membership. CREST-accredited for penetration testing, vulnerability assessment, incident response, security operations centre, cyber threat intelligence and threat led penetration testing. Verified: CREST Marketplace listing.

5. Pen Test Partners

Pen Test Partners is a UK penetration testing consultancy whose finance sector page lists banks, building societies and lenders, payment service providers, fintechs, and insurers and brokers among the organisations it works with, and describes red teaming under frameworks such as CBEST, GBEST, STAR-FS and TIBER. CREST-accredited for penetration testing, vulnerability assessment, incident response and threat led penetration testing. Verified: CREST Marketplace listing.

6. Claranet Cyber Security

Claranet is a managed services and cyber security group with a banking penetration testing page that states 400+ days of penetration testing delivered annually for Tier 1 banks. CREST-accredited for penetration testing, vulnerability assessment, security operations centre, and application and mobile application security testing. Verified: CREST Marketplace listing for Claranet Cyber Security.

7. Precursor Security

Precursor Security is a UK offensive security consultancy with a financial services sector page for banks, insurers, payment processors and fintech companies that mentions DORA and FCA PS21/3. It also publishes pricing: its cost page states engagements from £2,500 at approximately £1,200 per consultant day, with a 30-day retest, and its penetration testing page states a report within 5 working days of test completion. CREST-accredited for penetration testing, vulnerability assessment and security operations centre. Verified: CREST Marketplace listing.

8. Sentrium

Sentrium is an independent UK penetration testing consultancy with a financial services and fintech page that stresses testing without disruption to critical live systems. Its penetration testing page states a free retesting window to validate fixes. Its service pages give indicative price ranges by test type. CREST-accredited for penetration testing. Verified: CREST Marketplace listing.

9. Kroll (incorporating Redscan)

Kroll is a global risk advisory firm whose UK cyber practice absorbed Redscan. Redscan’s financial services cyber security page and a case study on uncovering vulnerabilities across a bank’s estate show its work in the sector. Kroll holds CREST accreditation for penetration testing, incident response and security operations centre. Redscan has no standalone listing, so check the Kroll entry. Verified: CREST Marketplace listing for Kroll LLC.

How we selected these companies

Every company on this list passed the same two entry checks: a live listing in the CREST Marketplace supplier directory confirming penetration testing accreditation, and public evidence of work with banks and other regulated financial firms. We then recorded what each company publishes about pricing, retests and report turnaround. All pages were checked on 7 October 2026.

• CREST accreditation, verified. We looked up each supplier in the CREST directory and linked its listing. No listing, no entry: brands absorbed into a parent company appear under the parent. Where a listing shows threat led accreditations such as CBEST or STAR-FS, we say so; where it does not, we say nothing.
• Financial services sector evidence. A general penetration testing company was not enough. Each entry needed a public page showing financial services work: a dedicated financial services or banking page, a bank case study, or regulated financial firms named among its clients. Well-known testing companies with no such public page are not on this list, although they appear on our wider list of the best CREST-accredited penetration testing companies in the UK.
• Published pricing. We recorded whether a company publishes its own prices on a public page. General statements about what the market charges were not counted as a company’s own pricing.
• Retests and report turnaround. A regulated financial firm usually has to prove that findings were fixed, and often to an audit committee’s deadline. Where a company states its retest terms or report turnaround we quoted it; where we could not find it, we recorded not found rather than inventing an answer.

How the companies compare

All nine companies hold verified CREST penetration testing accreditation, show a United Kingdom headquarters on their listing except Kroll, and have public financial services evidence. The practical differences are in what they publish.

Accreditation is taken from each company’s CREST Marketplace listing. Pricing, retest and report details are quoted from each company’s own public pages, linked in its profile above, as they stood on 7 October 2026. Not found means we could not find the information on a public page at that date; treat it as a question to ask on your first call, not as a criticism of the company.

Do banks and other financial services firms have to have a penetration test?

No general rule for UK banks, building societies and asset managers names a penetration test as mandatory. The duties that lead firms to commission one come from operational resilience. The FCA’s SYSC 15A applies under SYSC 15A.1.1R to banks, designated investment firms and building societies, among others. SYSC 15A.2.1R requires a firm to identify its important business services, and SYSC 15A.5.1R requires a testing plan showing how it will gain assurance that it can remain within its impact tolerances. The PRA’s Supervisory Statement SS1/21 sets out its expectations for the same regime, and PRA and FCA dual-regulated firms work to both. A penetration test can identify exploitable weaknesses in the systems those services depend on; demonstrating resilience also needs broader scenario testing and evidence of response and recovery.

CBEST and STAR-FS are different. They are scheme tests for firms the regulators select, not a general obligation. In the Bank of England’s CBEST implementation guide, the regulator notifies a firm in writing that a CBEST is requested, and the providers engaged must be accredited CBEST service providers. CREST describes STAR-FS as part of the PRA and FCA supervisory toolkit, delivered by STAR-FS accredited providers. Which provider you need depends on what your requirement states: a scheme test needs a provider approved for that scheme, and a CREST-accredited penetration test can come from a CREST-accredited company such as EJN Labs. Its place is the application, API, infrastructure and cloud testing around them, which finds weaknesses in the systems behind your important business services before a scheme test does.

For firms with EU exposure, Article 26 of the Digital Operational Resilience Act (Regulation (EU) 2022/2554) requires financial entities identified by their competent authority, other than microenterprises, to carry out threat-led penetration testing at least every 3 years, a frequency the authority may vary. It applies only to identified entities, not to every financial firm. Separately, UK GDPR Article 32(1)(d) requires a process for regularly testing the effectiveness of your security measures, without naming penetration testing as the method. In practice the request usually comes from inside the firm, from internal audit and risk committees, or from clients during due diligence. See also our guide for fintech firms, which covers payments and PCI DSS.

What a financial services firm should ask a penetration testing company

1. Which legal entity holds your CREST accreditation? Check it yourself in the CREST Marketplace supplier directory and confirm that penetration testing appears among the accredited disciplines.
2. Are you approved for CBEST or STAR-FS, or will you test around them? If your regulator has asked for a scheme test you need an approved provider, so ask which scheme approvals the company holds and where they are listed.
3. Can you test systems that support our important business services without putting us outside our impact tolerance? Ask how disruptive checks are handled on live systems and whether out of hours testing is available.
4. Where are the testers based, and who will see our data? Client records and transaction data may be visible during testing, so ask where the people doing the work are located and how findings are stored.
5. Is a retest included, and for how long? Internal audit and clients ask for evidence that findings were fixed, so a retest that is capped or charged separately changes the real price. Ask also when the report arrives and whether it suits an audit committee pack.
6. What is the fixed price for our scope? Ask for a day count and a day rate, not a range.

Get a quote

Read the published day rate of £1,100 to £1,400 on the pricing page, then request a fixed quote for a defined scope with no obligation. Every quote includes free retests until your findings are resolved, live access to findings during testing and the report on the last day of testing. Get a penetration testing quote, or read more about penetration testing for UK financial services.

Related: Penetration Testing Under FCA Operational Resilience: What Regulated Firms Must Evidence and Penetration Testing Cost for UK Banks, Wealth and Pensions Firms.