---

name: prompt-pack-challenge-to-arbitrator
description: Use when a party to arbitration needs to draft a formal challenge to an arbitrator based on conflicts of interest, lack of impartiality, or lack of independence. Covers ICC, LCIA, DIAC, ADGM, SIAC, and UNCITRAL rules; addresses the IBA Guidelines on Conflicts of Interest; and flags MENA-specific considerations including challenge procedures under UAE, DIFC, KSA, and Lebanon arbitration law.
license: MIT
metadata:
id: prompt-pack.challenge-to-arbitrator
category: prompt-pack
practice_area: arbitration
priority: P2
intent: [drafting, challenge-to-arbitrator, arbitrator-challenge, impartiality, independence, conflict-of-interest]
related: [prompt-pack-arbitration-statement-of-claim, prompt-pack-case-assessment-memo, prompt-pack-demand-letter, prompt-pack-arbitration-award-enforcement]
source: Louis — HAQQ Legal AI (github.com/sboghossian/mini-claude-for-legal)
version: "1.0"

Challenge to Arbitrator

An arbitrator challenge is a high-stakes procedural step: the threshold for success is deliberately set high, and a failed challenge can damage credibility before the tribunal while strengthening the opponent's position. A well-crafted challenge must be factually precise, legally grounded in the applicable rules, and filed within strict time limits.

When to use this

• A party has discovered facts that give rise to justifiable doubts about an arbitrator's impartiality or independence under the applicable rules.
• New information about an undisclosed relationship between an arbitrator and the opposing party or its counsel has surfaced during proceedings.
• An arbitrator has made procedural rulings that, taken together with other circumstances, suggest bias.
• The arbitration clause or the rules specify a challenge procedure and a deadline is imminent.

Do not use this skill to bring tactical or dilatory challenges — challenge grounds must be genuine. Filing a groundless challenge can expose the challenging party to adverse costs and sanctions.

Required inputs

Input	Why it matters	Sensible default
Arbitration case reference or proceeding name	Identifies the proceeding formally	Ask the user
Arbitrator's name and role (sole, presiding, co-arbitrator)	The challenge is directed at a specific individual	Ask the user
Grounds for the challenge (conflict of interest / lack of impartiality / lack of independence)	The legal basis for the challenge	Ask the user to describe the specific facts giving rise to the challenge
Applicable arbitral rules	The procedural framework determines how and to whom the challenge is filed	Ask the user: ICC / LCIA / DIAC / ADGM / SIAC / UNCITRAL / ad hoc
Date when the challenging party became aware of the grounds	Most rules start a short time limit from date of knowledge	Ask the user — this is critical
Supporting evidence	The challenge must be supported by documentary proof	Ask the user to attach or describe available evidence

Optional inputs

• Prior communications from or with the arbitrator on the relevant relationship.
• The arbitrator's curriculum vitae or published disclosures (IBA Orange/Red List background check recommended).
• Whether the challenge is also being raised as a set-aside ground (post-award) as a fallback.
• Whether local counsel in the seat jurisdiction needs to be involved.

Document structure

1. Heading / identification

• Case name and reference number.
• Names of the parties.
• Name of the institution (if any) or the co-arbitrators if an ad hoc challenge.
• Date of the challenge.
• Name of the challenging party and its counsel.

2. Procedural basis

• Cite the specific rule under which the challenge is filed (e.g., ICC Rules Art. 14–15; LCIA Rules Art. 10; DIAC Rules Art. 13; UNCITRAL Rules Art. 12–13; DIFC Arbitration Law Art. 13).
• State that the challenge is filed within the applicable time limit, citing the date of knowledge and the date of the challenge.
• If the time limit is close to expiry, note that the challenge is filed without prejudice to any rights that may arise from subsequently discovered facts.

3. Standard to be applied

• Most rules apply a "justifiable doubts" standard (UNCITRAL Model Law Art. 12(2)): circumstances that give rise to justifiable doubts about the arbitrator's impartiality or independence, judged objectively.
• The IBA Guidelines on Conflicts of Interest in International Arbitration (2014, updated 2024) provide the authoritative framework; the Red List identifies non-waivable conflicts, the Orange List waivable ones.
• Some institutional rules (LCIA, SIAC) apply a slightly higher standard of "real danger of bias"; flag if the applicable rules differ.

4. Statement of facts

Provide a precise, chronological factual narrative:

• The relationship, connection, or conduct that gives rise to the challenge.
• When and how the challenging party discovered these facts.
• What disclosure, if any, the arbitrator made and when.
• Any prior knowledge the challenging party had (which may affect the timeliness argument).

Keep this section strictly factual; argument comes in the next section.

5. Legal analysis

Map the facts to the applicable standard:

• Identify the specific category of conflict or bias ground (e.g., financial interest, prior representation, personal relationship, unconscious bias arising from conduct in proceedings).
• Cite the relevant IBA Guidelines category (Red, Orange, or Green list item).
• Apply the objective "justifiable doubts" test: would a fair-minded, informed observer have justifiable doubts?
• Address any disclosure failure separately: non-disclosure of a fact that should have been disclosed itself constitutes grounds under most rules, even if the underlying conflict would otherwise be waivable.

6. Relief requested

• Primary: disqualification of the named arbitrator from the proceedings.
• Consequential: suspension of the arbitral proceedings pending determination of the challenge.
• Costs: the challenging party's costs of the challenge, particularly if the arbitrator or institution caused delay by failing to disclose.

7. Evidence schedule

List all documents submitted in support, numbered sequentially as Exhibits C-1, C-2, etc.

Jurisdictional and rules-specific notes

Forum / Seat	Challenge procedure
ICC	Filed with the ICC Court of Arbitration; other party and arbitrator comment; Court decides without giving reasons; non-recourse to state courts during challenge
LCIA	Filed with the LCIA Court; full written submissions; LCIA Court decides; strictly confidential
DIAC (Dubai)	Filed with the DIAC; challenge decided by remaining tribunal or DIAC; governed by UAE Federal Arbitration Law No. 6 of 2018
DIFC Arbitration Centre	DIFC Arbitration Law Art. 13 (UNCITRAL Model Law basis); challenge decided by institution or, failing agreement, DIFC Court
ADGM	ADGM Arbitration Regulations (2015); Model Law based; challenge decided by ADGM Court if institution fails to act within 30 days
UNCITRAL (ad hoc)	Challenging party notifies other party and tribunal within 15 days of knowledge; if not agreed, party may request national court to decide (seat's arbitration law governs)
KSA	Saudi Arbitration Law (Royal Decree No. M/34, 2012); challenge filed with arbitral institution or competent court; Arabic proceedings required for domestic disputes
Lebanon	Lebanese Arbitration Law (NCPC Arts. 762 et seq.); challenge before the president of the court of first instance if no institutional mechanism applies

Common mistakes

• Missing the time limit. Most rules require the challenge within 15–30 days of knowledge of the grounds. Missing this deadline forfeits the right to challenge (though the right to rely on the ground as a set-aside ground post-award may survive).
• Confusing tactical delay with genuine grounds. Institutions and courts are sophisticated; unfounded challenges are dismissed, often with costs.
• Insufficient factual support. "Apparent bias" from rulings alone is very rarely sufficient; concrete relationship facts are required.
• Failing to distinguish the IBA list category. Red List conflicts are non-waivable; Orange List conflicts can be waived by parties with knowledge; characterizing a Red List situation as Orange can be challenged by the institution.
• Not considering the seat court as a fallback. If the institution rejects the challenge, the seat's national arbitration law may allow an application to the national court within a further limited period.

Related skills

• [[prompt-pack-arbitration-statement-of-claim]]
• [[prompt-pack-case-assessment-memo]]
• [[prompt-pack-demand-letter]]
• [[prompt-pack-arbitration-award-enforcement]]
• [[prompt-pack-arbitration-interim-measures]]