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Methodology

Built on primary sources.

Every rule encoded in Deadline Engine is traceable to its statutory instrument, practice direction, or tribunal rule. No aggregator summaries. No AI paraphrasing of legislation.

How a rule becomes code

  1. A rule is identified from its primary source: the Civil Procedure Rules, a Practice Direction, the Employment Tribunal Rules 2013, the FCA Handbook, the First-tier Tribunal (Tax Chamber) Rules, the Immigration (Appeals) Procedure Rules, the Housing Grants, Construction and Regeneration Act 1996, or similar.
  2. The rule is encoded as a typed record in the codebase, with the period, the trigger event, the counting method (calendar days, business days, clear days, FPR clear days, HGCRA days, calendar months), and a citation.
  3. Worked examples are drawn from The White Book, Blackstone’s Civil Practice, and the official guidance notes for each tribunal. The computed output is compared against each example.
  4. A test suite of 2,651 assertions covers every rule and adjustment, including bank-holiday and Christmas/Easter edge cases. Tests run on every code change.

Primary sources used

  • Civil Procedure Rules (CPR)
  • CPR Practice Directions
  • Pre-action Protocols
  • Family Procedure Rules (FPR)
  • Criminal Procedure Rules 2025
  • Employment Tribunal Rules 2013
  • Limitation Act 1980
  • Insolvency Act 1986 and Rules 2016
  • Companies Act 2006
  • HGCRA 1996
  • FCA Handbook (DEPP, DISP)
  • First-tier Tribunal Rules (Tax, IAC)
  • TCPA 1990, Landlord & Tenant Act 1954
  • Renters’ Rights Act 2025

Bank holidays and court closures

Bank holidays are fetched live from the GOV.UK bank holidays feed (gov.uk/bank-holidays), cached for 24 hours. Good Friday is computed from the Anonymous Gregorian Easter algorithm. Christmas Day is hard-coded. Court office closure periods (CPR 2.8(5)) are encoded as additional closure sets.

Review cadence

Rules are reviewed on a rolling basis when the relevant statutory instrument is updated. Major review points: start of each Michaelmas term (October), when CPR amendments typically take effect; start of each tax year (April) for tax tribunal timelines; and on commencement of any Act of Parliament that materially affects an encoded rule.

Reporting an error

If you identify a calculation you believe is wrong, email hello@deadlineengine.com with the trigger date, practice area, and expected result. We investigate every report within 72 hours and publish corrections in the changelog.

Built by a lawyer

Deadline Engine is built by Victor Humenhuk, a lawyer trained at Freshfields with an LLM in International Commercial and Technology Law from the University of Manchester. Every rule is hand-encoded from primary sources and reviewed against worked examples in the authoritative practitioner texts.