Prohibitory Injunctions

This guide touches on an important tool in litigation – the prohibitory injunction.

1. Why every growth business needs an “injunction plan”

Fast-moving start-ups and scale-ups often assume that litigation is something for larger, slower organisations. Reality bites the first time a departing developer uploads your source code to GitHub, or a disgruntled reseller leaks unreleased product specs on social media the night before launch. Where money damages after the event will not put the genie back in the bottle, the nuclear button is a prohibitory injunction – a court order telling the other side stop now, or face contempt of court.

Because the pace of harm in the digital economy is measured in hours, the ability to secure fast injunctive relief is mission-critical for founders, ops directors and in-house counsel. This guide explains:

• what a prohibitory injunction is and how it differs from other interim remedies;
• the up-to-date legal tests under CPR 25 after the 179th Practice Direction Update (in force 6 April 2025);
• the practical evidence you must marshal within 24–48 hours;
• a step-by-step map of what your lawyer will actually do, from the first “dawn raid” preservation letter to the return date hearing; and
• common pitfalls for SMEs (cross-undertakings in damages, funding, cost-budgeting pilots, and more).

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2. What is a prohibitory injunction?

A prohibitory injunction is a court order that bars the defendant from taking (or continuing) a particular action – for example, disclosing confidential information, infringing a trade mark, or diverting key customers. It is distinct from:

• Mandatory injunctions, which compel positive action such as handing over data or removing infringing material. (The courts treat these as more draconian, and since 6 April 2025 they are governed by a revised CPR 25 with a new model “Search and Imaging” order.)
• Freezing (asset-preservation) injunctions, which stop a defendant dissipating assets and rely on a recently clarified “serious issue to be tried / good arguable case” threshold.

In practice, most business-critical injunctions are sought interim (i.e. before trial) and on very short notice; a final injunction can then be sought at trial once liability is established.

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3. Why start-ups and SMEs are frequent applicants

Entrepreneur-led companies face a unique mix of vulnerabilities:

Threat scenario	Typical impact	Why money isn’t enough
Ex-employee uploads source code to public repo	Loss of trade secret, competitive edge evaporates	Once code is public, damages can’t un-publish it
Influencer leaks confidential product roadmap	Competitive timing advantage lost, investor confidence shaken	Speed matters more than later damages
Competitor scrapes entire customer database	GDPR risk, loss of recurring revenue	Data can be copied indefinitely; compensation alone won’t fix churn
Supplier threatens to terminate sole-source component supply in breach of contract	Production line halt, reputational damage	Subsequent damages claim does not restart deliveries in time

For each scenario, the core test is whether the harm is “immediate and irreparable.”

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4. The legal framework in 2025

1. Statutory power – Senior Courts Act 1981, s.37.
2. Civil Procedure Rules – CPR Part 25 (as overhauled on 6 April 2025). The revamp folded the old PD 25A into the Rules and introduced a mandatory model order for Search & Imaging applications, plus tighter rules on evidence by affidavit.
3. Case-law test – still anchored in American Cyanamid v Ethicon (1975) but refined:
   • Serious issue to be tried (low merits threshold).Inadequacy of damages – would money after trial make you whole?Balance of convenience / justice – which party suffers more if the court gets it wrong?Status quo preservation – strong modern emphasis, especially for short-term PIs.
   Recent Court of Appeal authority in Dos Santos v Unitel SA (2024) expressly equates the “good arguable case” test for freezing orders with the American Cyanamid “serious issue” standard, ensuring consistency across interim relief.
4. Cross-undertaking in damages – the applicant must promise to compensate the respondent for losses if the injunction later proves wrongful. Early cost-budgeting pilots (CPR PD 51ZG1/2) mean SMEs must forecast worst-case exposure up front.
5. Disclosure & preservation duties – the expanded Search/Imaging order practice recognises the reality of cloud storage and BYOD devices, allowing forensic evidence capture without full “Anton Piller” search-and-seize intrusions.

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5. The American Cyanamid checklist in plain English

Test limb	What you must show	Startup-friendly evidence tips
Serious issue to be tried	Your claim is more than speculative	Internal Slack logs, code commit history, signed NDAs, contract excerpts
Damages inadequate	The harm cannot be fixed with money	Screenshots of early-access leak, investor e-mails threatening to pull
Balance of convenience	Overall justice favours granting the order	Impact timetable vs. defendant’s cost of restraint
Status quo	Injunction preserves current state pending trial	Explain how defendant’s next step will change business landscape irreversibly

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6. Typical fact patterns triggering a prohibitory injunction

1. Confidential information & trade secrets – e.g., algorithms, customer lists.
2. IP infringement – counterfeit apps, domain hijacking, unlicensed software forks.
3. Employment restraints – garden-leave breaches, non-compete or non-solicitation violations.
4. Brand & reputation attacks – false comparative advertising, social-media impersonation.
5. Supply-chain choke points – threatened contract termination leaving no alternative source.

Time is of the essence: delay (“acquiescence”) can itself defeat an application.

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7. What your lawyer actually does – a step-by-step timeline

Stage & time-frame	Lawyer actions	Your internal actions
T-48 hrs: triage call	Conflict check, identify cause of action and forum (High Court – Business & Property Courts for most tech/IP matters). Estimate urgency (without notice vs. on-notice).	Collate contracts, NDAs, screenshots, Git logs, marketing drafts. Nominate witnesses who can sign statements quickly.
T-40 hrs: evidence capture	Draft preservation letter threatening proceedings; advise on self-help (locking accounts, revoking VPN tokens). Commission independent IT forensic expert if an Imaging Order may be required.	Stop internal comms chatter, implement litigation hold on e-mails and cloud drives.
T-30 hrs: pleadings & exhibits	Prepare Claim Form and Application Notice (Form N244), plus Draft Order (based on new model if search/imaging) and Skeleton Argument. Include cross-undertaking wording and schedule of costs.	Prepare director’s witness statement setting out timeline, screenshots, risk of harm. Sign and scan as statement of truth.
T-24–12 hrs: ex parte hearing prep	Book urgent slot before a duty judge (Commercial Court Listing Office). Assemble authorities bundle: American Cyanamid, Dos Santos, any sector-specific precedent. Serve sealed certificate of compliance with PD 25.	Authorise solicitors to give undertaking on your behalf; arrange funding (ATE insurance / litigation finance) if needed.
H-0: without-notice hearing (30–60 mins)	Counsel takes judge through Skeleton. Judge may grant order, require undertakings, or direct on-notice hearing. If granted, lawyer arranges personal service via process server; instructs supervising solicitor/IT expert for search/imaging if applicable.	Have ops team on standby to assist server and expert (e.g. to locate devices).
H+0–48 hrs: execution & compliance	Attend premises (if search/imaging), serve order, ensure respondent understands penal notice. File certificate of service.	Keep internal log of any interference or obstruction; gather evidence for return date.
Return date hearing (usually 7–14 days)	Respondent appears; court reviews whether to continue, vary or discharge injunction. Applicant files supplemental evidence; negotiates undertakings in lieu of injunction.	Decide strategic outcomes: settlement, mediation, or proceed to full trial.
Post-injunction management	Monitor compliance; issue contempt application if breach. Prepare for disclosure, costs budgeting (PD 51ZG pilots) and potential summary judgment.	Maintain strict confidentiality, continue collecting loss data to prove damages if needed.

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8. Common hurdles and how to address them

• The cross-undertaking elephant – A well-capitalised defendant may demand security. Start-ups can mitigate by offering capped undertakings, ATE insurance or third-party deed polls.
• Delay – The court expects immediate action once you are aware of the threat. Keep documented decision logs explaining any unavoidable lag (e.g. overnight forensic analysis).
• Forum confusion – Intellectual-property injunctions now sit exclusively in the Business & Property Courts. Issuing in the wrong court wastes precious time.
• Evidential gaps – Hearsay is permissible on an interim application, but the weaker your exhibits, the higher the risk the judge refuses. Invest early in screenshots, hash values and audit-trail exports.
• Over-broad orders – The 2025 model search/imaging order requires applicants to justify every deviation. Carefully tailor the prohibited acts to avoid judicial push-back.

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9. Funding and cost management for SMEs

• ATE insurance now routinely covers adverse cross-undertaking exposure up to £2 m.
• Third-party litigation funding is increasingly available for IP-heavy start-ups with strong merits.
• Fixed-fee “rapid response” retainer packages are offered by many dispute boutiques; consider negotiating one before trouble strikes.
• Cost-budgeting pilots (PD 51ZG1/2) mean early budgets are more granular; involve finance teams from day one.

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10. Practical compliance tips (to avoid needing an injunction at all)

1. Contract hygiene – Use well-drafted NDAs with express injunctive-relief clauses and English jurisdiction.
2. On-boarding & exit interviews – Remind employees of IP/confidentiality duties; collect devices immediately.
3. Data-loss prevention tooling – Flag bulk exports of source code or customer lists in real time.
4. Brand monitoring – Automated alerts for domain name registrations and social-media impersonation.
5. Evidence culture – Train staff to capture time-stamped screenshots and compile incident chronologies.

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11. Conclusion

A prohibitory injunction is one of the most potent – and expensive – tools in English civil procedure. For founder-led businesses the decision to “go nuclear” often lands on the CEO’s desk at 3 a.m. Understanding the American Cyanamid test, the 2025 CPR changes, and the precise play-book your lawyers will follow turns panic into a disciplined, board-approved response. Preparation – contractual, technical and cultural – is both your best sword and your cheapest shield.

If you need help with an injunction, fill in the form to the right and we will connect you with a lawyer who can advise you on next steps and give you a quote.