From Slip to Solution: The Adjudicator’s Power to Amend

Factual Background

The adjudication process under the Housing Grants, Construction and Regeneration Act 1996 , (as amended) (“the Construction Act“), is designed to provide swift and binding interim resolution of disputes in the construction industry. A key procedural safeguard within this framework is the “slip rule,” which permits adjudicators to correct accidental errors in their decisions.

Statutory Framework

The slip rule is codified in section 108(3A) of the Construction Act. This provision mandates that construction contracts must include a term allowing adjudicators to correct clerical or typographical errors arising from accidental slips or omissions.

Further clarity is provided in paragraph 22A of the Scheme for Construction Contracts (England and Wales) Regulations 1998 (as amended by SI 2011/2333) (“the Scheme“). The Scheme stipulates that such corrections must be made within five days of the decision being delivered to the parties. Importantly, any correction made under this rule is deemed to form part of the original decision.

Scope and Limitations

The slip rule is narrowly confined to genuine clerical or typographical mistakes that do not alter the adjudicator’s original reasoning or intention. This includes errors in expression, calculation, or transposition—such as misnaming parties or arithmetical mistakes. However, it does not extend to substantive revisions or reconsiderations of the adjudicator’s decision.

Judicial Interpretation

Case law has played a pivotal role in delineating the boundaries of the slip rule:

• Axis M&E UK Ltd and Axis Plumbing NSW PTY Ltd v Multiplex Construction Europe Ltd

In Axis M&E UK Ltd and another v Multiplex Construction Europe Ltd [2019] EWHC 169 (TCC), the adjudicator corrected calculation errors, reversed liability for costs, and added interest. The court upheld these amendments, finding them consistent with the adjudicator’s original intention and within the permissible scope of the slip rule.

Case Summary

Axis, subcontractors for Multiplex, disputed the valuation of their work and the sum due under an interim payment application. The adjudicator initially erred in calculating the sum payable, concluding that no payment was due. Upon correction, the decision was amended to require Multiplex to pay £654,119.65, along with interest and a reversal of liability for adjudication fees.

Multiplex challenged the amendment, arguing it exceeded the scope of the slip rule. The court, relying on ROK Building Ltd v Celtic Composing Systems Ltd EWHC 2664 (TCC), held that the adjudicator had properly understood the dispute referred to him and had not erred in his decision-making process.

The court concluded that there was no relevant distinction between arbitration and adjudication in this context. It found that the slip rule could extend to correcting arithmetical errors and making consequential amendments, such as awarding interest and reversing fee liability.

The court ruled in favour of Axis, affirming that the slip rule permits corrections to the principal sum and consequential adjustments, provided they reflect the adjudicator’s original intention. This case highlights the broader application of the slip rule beyond typographical errors to include arithmetical corrections and related amendments.

• Bloor Construction (UK) Ltd v Bowmer & Kirkland (London) Ltd [2000] EWHC 183 (TCC)

Similarly, in Bloor Construction (UK) Ltd v Bowmer & Kirkland (London) Ltd [2000] EWHC 183 (TCC), the court enforced a corrected decision involving a payment calculation error, recognising that the slip rule was implied in the contract due to the Scheme.

Case Summary

The dispute arose between the parties regarding the valuation of work and payment obligations under a construction contract. The adjudicator initially made an error in calculating the sum payable, which was later corrected to reflect the intended decision. The correction included adjustments to the principal sum, interest, and adjudication fees.

The Bowmer & Kirkland contested the correction, arguing that it exceeded the scope of the slip rule, which is typically limited to clerical or typographical errors. The court, however, upheld the adjudicator’s correction, emphasising that the slip rule could extend to arithmetical errors and consequential amendments, provided they aligned with the adjudicator’s original intention and do not involve a substantive reconsideration of the decision.

This case underscores the importance of the original intention within the adjudicator’s discretion in applying the slip rule and highlights its broader application beyond typographical errors to include arithmetical corrections and related adjustments. It also reinforces the principle that corrections must be made within the procedural framework of the Scheme.

• CIB Properties Ltd v Birse Construction Ltd [2004] EWHC 2365 (TCC)

Case Summary

In CIB Properties Ltd v Birse Construction Ltd [2004] EWHC 2365 (TCC), Birse complained to the adjudicator that he had made a slip in the award and said that he had jurisdiction to, and therefore should, remedy it.

The adjudicator responded by saying that if “the parties or the court decide that there is any error I should be happy to review the decision and to receive further submissions from the parties…” Birse claimed that this was an invitation for the court to review the matter and refused to pay. CIB applied to the court to enforce the award.

The issues that arose in court were:

• Whether a “dispute” had crystallised before the referral to adjudication, given that, so Birse argued, discussions were still ongoing at the time of the referral;
• The conduct of CIB before the notice of adjudication did not render the whole process unfair or put Birse at an overwhelming disadvantage, nor had CIB acted in bad faith in not explicitly referring to the possibility of an adjudication in its discussions and correspondence with Birse;
• Whether some disputes were so complex that, having regard to the provisions of section 108 of the Housing Grants, Construction and Regeneration Act 1996 (“the Act”), they were not suitable for adjudication; and
• Whether, in the light of the adjudicator’s letter, the court could review a matter which the defendant claimed was a slip.

In relation to each of these issues, the court held:

That the claim notified by CIB on 28 July 2003 was disputed by Birse and that the dispute had therefore crystallised by the date of the referral on 14 November 2003. The court said that in the 15 intervening weeks there had been a proper opportunity for Birse to consider the claim and provide a constructive response which may or may not have led to further discussion. Instead, it said, Birse attempted to manoeuvre tactically so that it could make the claim that the dispute had not crystallised. Accordingly, the adjudicator did have jurisdiction.

That it was clear that the claim was complex and therefore if the adjudicator was to reach a fair decision he clearly needed more than the 42 days to which he was statutorily entitled under the Act (provided that CIB, as the referring party, had agreed). In these circumstances, more than 42 days were needed and the adjudicator sought and obtained the agreement to extensions of time. This enabled him to reach a fair conclusion, having given both parties a proper opportunity to put their case.

Even if the adjudicator had invited the court to determine whether the matter complained of had been a slip, it would not be open to the court’s review. The court said that adjudication was intended to be an interim process which, if carried out fairly and in a manner which is procedurally correct, is not subject to review by a court.

The court concluded that the adjudicator’s decision should be enforced.

Conclusion on the slip rule in adjudication

The slip rule serves as a pragmatic mechanism to uphold the integrity of adjudication decisions by allowing the correction of inadvertent errors. Courts have consistently supported its application where corrections are limited to clerical or typographical slips, made promptly, and do not prejudice the parties. It is therefore especially important to ensure that construction contracts expressly incorporate this provision and remain vigilant in identifying and addressing such errors within the statutory timeframe.

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