The Best Red Team Companies in the UK (2026)

The best red team companies in the UK in 2026 are listed below. Each one holds a CREST penetration testing accreditation and runs a dedicated red team or adversary simulation service on its own public page, and each is compared on published pricing, retests and report delivery, so you can see what an exercise is likely to involve before the first call.

1. MDSec

MDSec is a UK security consultancy whose adversary simulation practice is built around red teaming. Its red team operations page describes kill chain aligned operations, objective-led assumed breach assessments, physical and social engineering assessments, and states that its operations are delivered under and in line with the CREST STAR, Bank of England CBEST and TIBER frameworks. The CREST listing shows Penetration Testing, Vulnerability Assessment, Incident Response, Threat Led Penetration Testing and TLPT-FS Threat Led Penetration Testing. Verified: CREST Marketplace listing.

2. EJN Labs

EJN Labs is a CREST-accredited UK penetration testing consultancy with a dedicated red teaming and adversary simulation service. It is intelligence-led and mapped to the MITRE ATT&CK tactics, from reconnaissance and initial access through privilege escalation and lateral movement to exfiltration, and covers phishing, pretext calls and, where authorised, physical access attempts. The starting price for red teaming is £15,000, taken directly from the pricing page. Focused, at £15,000 to £35,000, covers 1 to 2 attack vectors over 2 to 3 weeks. Full Adversary Simulation, at £35,000 to £75,000, runs 3 to 5 weeks. The Threat-Intelligence-Led tier, from £75,000, runs 5 to 6 weeks. EJN Labs is one of two companies on this list that publish pricing for red teaming. Verified: CREST Marketplace listing for EJN Labs.

Every engagement is a fixed price for a defined scope, quoted within 24 hours of a 30-minute scoping call. The published day rate for its CREST-certified consultants is £1,100 to £1,400, and red team engagements begin with a 1 to 2 week threat-intelligence phase before active operations. Retesting of fixed findings is free until every finding is closed. By EJN Labs’ own figures, free retests save clients up to 35% against paying for retesting separately, and free rescheduling means a slipped release date costs nothing. There are no callout, cancellation or out-of-hours fees.

Findings are posted to a client portal as they are confirmed. The report arrives on the last day of testing, and EJN Labs is the only company on this list that states when the report arrives. Each finding is CVSS scored with remediation guidance, and every engagement ends with a signed letter of attestation. Testing is by UK-based, CREST-certified penetration testers, safe-by-default on production with no denial of service, ransomware simulated in no-impact mode and out of hours slots. The business holds ISO 27001, ISO 9001, Cyber Essentials and Cyber Essentials Plus. Where a requirement names a regulator’s scheme such as CBEST or TIBER-EU, use a provider approved for it. Where it asks for a CREST-accredited red team or penetration test, a CREST-accredited company such as EJN Labs meets it.

MDSec’s specialism in red teaming and its published scheme alignment keep it first. On the criteria this page can verify from public pages, which are pricing, retests and report delivery, EJN Labs has the most complete published answer, with free retests until every finding is closed and a report on the last day of testing, which is why it sits second.

3. NCC Group

NCC Group is a UK cyber security company. Its attack simulation page describes simulated red team and black team attacks, purple team improvement work and gold team crisis management exercises, plus a regulatory simulated attack service for CBEST, TIBER-EU and similar regimes. The CREST listing shows Penetration Testing, Threat Led Penetration Testing, TLPT-FS Threat Led Penetration Testing and Threat Intelligence for Simulated Attack, among other disciplines. Verified: CREST Marketplace listing.

4. Pen Test Partners

Pen Test Partners is a UK security consultancy with a dedicated red teaming page that describes an objective-based assessment taking the view of an adversary, with a wider scope that can include physical and social engineering. The CREST listing shows Penetration Testing, Vulnerability Assessment, Threat Led Penetration Testing and TLPT-FS Threat Led Penetration Testing. Verified: CREST Marketplace listing.

5. JUMPSEC

JUMPSEC is a UK offensive security consultancy whose red teaming page describes a customised adversary simulation service, states alignment with TIBER-EU and DORA, and describes its red teaming as CREST STAR-certified. The CREST listing shows Penetration Testing, Vulnerability Assessment, Incident Response, Threat Led Penetration Testing and AI-Enabled Penetration Testing. Verified: CREST Marketplace listing.

6. Precursor Security

Precursor Security is a UK offensive security consultancy with a red team operations page that states CREST-accredited red team operations with a published starting price, standard exercises running several weeks, and a re-test consultation to verify that critical detection gaps are closed. It combines physical intrusion, social engineering and network exploitation, and states that its methodology is aligned with MITRE ATT&CK, CBEST and TIBER-EU. The CREST listing shows Penetration Testing, Vulnerability Assessment and Security Operations Centre. Verified: CREST Marketplace listing.

7. Bridewell

Bridewell is a UK cyber security services company with a red team assessment page that describes insider threat testing and physical access scenarios, and offers assumed breach penetration testing as an option alongside the assessment. The CREST listing shows Penetration Testing, Vulnerability Assessment, Incident Exercising and Threat Led Penetration Testing. Verified: CREST Marketplace listing.

8. Prism Infosec

Prism Infosec is a UK security consultancy whose red teaming page describes full-scale adversary emulation that simulates a number of potential cyber attacks on your organisation over an agreed period. The CREST listing shows Penetration Testing, Vulnerability Assessment, Incident Exercising, Threat Led Penetration Testing and TLPT-FS Threat Led Penetration Testing. Verified: CREST Marketplace listing.

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 whose accreditations include penetration testing, and a live, dedicated public page for red teaming or adversary simulation. We then recorded what each company publishes about pricing, retests and report delivery. All pages were checked on 24 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.
• A dedicated red team page. A home page that lists red teaming in a menu was not enough. Each entry needed its own public page for red teaming or adversary simulation. Well-known companies whose page we could not confirm 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 for red teaming on a public page. General statements about what the market charges were not counted as a company’s own pricing.
• Retests and report delivery. A red team exercise ends with detection gaps to close, and often a board or regulator waiting for evidence. Where a company states its retest terms or report timing we noted it; where we could not find it, we recorded not found rather than inventing an answer.
• Scheme statements. Where a company’s own page names a threat-led testing scheme, we say so in its profile, in its own words. The CREST listing shows which threat-led disciplines each company is accredited for.

How the companies compare

All eight companies hold verified CREST penetration testing accreditation, show a United Kingdom headquarters on their listing, and have a dedicated red team page. The practical differences are in what they publish.

Accreditation is taken from each company’s CREST Marketplace listing. Pricing, retest and report details are taken from each company’s own public pages, linked in its profile above, as they stood on 24 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 you have to have a red team assessment?

No general law requires a red team assessment. The requirement appears in scheme and regulator rules for named firms only. The Bank of England’s CBEST implementation guide sets out an intelligence-led testing framework for firms and financial market infrastructures, in which the regulator notifies the firm in writing that a CBEST is requested. The European Central Bank describes TIBER-EU as a European framework for threat intelligence-based ethical red-teaming. Under the EU Digital Operational Resilience Act, Article 26 provides for threat-led penetration testing of financial entities that their authority identifies, and the technical standards for it are listed on the ESMA DORA page.

If you are not a named firm, the duties that lead organisations to commission one are broader. UK GDPR Article 32 asks for appropriate security measures, including, as appropriate, a process for regularly testing, assessing and evaluating their effectiveness. A red team exercise is one way to test that your people, processes and detection work together, beyond what a penetration test of one system shows. In practice the request usually comes from a board, a cyber insurer, a customer or a regulator asking how well you would detect and contain a real attack.

Match the provider to the wording of the requirement. Where a requirement names a scheme such as CBEST or TIBER-EU, use a provider approved for it. Where it asks for a CREST-accredited red team or penetration test, a CREST-accredited company such as EJN Labs meets it. For scope and cost, see our guide to red teaming and adversary simulation.

What a buyer should ask a red team company

1. Which legal entity holds your CREST accreditation? Check it yourself in the CREST Marketplace supplier directory and confirm which disciplines appear, including any threat-led testing.
2. What is the objective, and who knows about the exercise? Agree the target outcome, the small group who are told in advance, and how the blue team will be handled.
3. Which techniques are in scope? Ask whether phishing, pretext calls and physical access attempts are included, and how each is approved in writing before it starts.
4. How do you protect production? Ask what is simulated rather than executed, such as ransomware, and what stops a live exercise disrupting the business.
5. Is a retest included, and what happens after the report? A detection gap you cannot prove closed will come back as the first question at the next review.
6. What is the fixed price for our scope, and when do we get the report? Ask for a duration and a price for the defined objective, not a range.

Get a quote

Read the red teaming starting price of £15,000 and the 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 red teaming with EJN Labs.