Extension of time for submitting tribunal response

The Employment Appeal Tribunal (EAT) has upheld an employment tribunal’s refusal to extend time for an employer to submit its ET3 response, which was filed approximately ten months late. The judgment emphasises the importance of responding promptly to tribunal correspondence and confirms that a false explanation for the delay may prove fatal to an extension application.

Costco Wholesale UK Ltd v Nash [2026] EAT 85 

Facts of the case 

Mr Nash was employed by Costco at its Chingford warehouse from July to September 2022 before being dismissed during his probationary period. He subsequently brought employment tribunal proceedings alleging direct race discrimination and harassment. The claim was received by the tribunal on 27 December 2022.

Costco did not submit a response to the claim (ET3) until 22 December 2023, almost ten months after the deadline had expired. It applied for an extension of time, arguing that it had been unaware of the claim until December 2023, when tribunal correspondence reached its head office.

However, the employment tribunal found that the company had, in fact, received multiple pieces of tribunal correspondence at the Chingford warehouse during 2023. It also found that six emails relating to the proceedings had been sent directly to the warehouse’s General Manager. The tribunal concluded that the emails had been received and deliberately deleted, rejecting the employer’s explanation that they had been diverted into a spam folder.

The tribunal therefore found that Costco’s explanation for the delay was untrue and that the company had chosen to do nothing despite repeated notifications of the claim. While recognising that Costco would be prejudiced by being unable to defend serious allegations of race discrimination, the tribunal also considered the prejudice caused to the claimant by the delay and concluded that the proposed defence did not appear particularly strong. Overall, it held that an extension of time was not in the interests of justice and refused Costco’s application.

Costco appealed, arguing that the tribunal had erred in its assessment of prejudice, applied the wrong approach to the merits of the defence, and failed properly to balance the relevant factors when assessing the interests of justice.

EAT decision

The EAT dismissed the appeal. It held that the employment tribunal had considered all relevant factors and had reached a conclusion that was well within the broad discretion afforded to it. 

In its judgment, the EAT provided detailed guidance on the applicable principles when determining an application for an extension of time, as established in the leading authority of Kwik Save Stores Ltd v Swain [1997] ICR 49:

• the explanation for the delay 
• the balance of prejudice between the parties 
• the apparent merits of the proposed defence. 

First, it confirmed that the three Kwik Save factors are discretionary rather than threshold tests. Tribunals are required to consider all relevant circumstances and undertake a holistic assessment rather than applying a mechanical formula.

Secondly, the EAT rejected the argument that a tribunal must decide, as a separate preliminary step, which party would suffer greater prejudice. Instead, prejudice to both parties can be assessed as part of the overall balancing exercise.

Thirdly, the EAT clarified that the merits of the defence are not a binary issue. The fact that a defence is arguable does not automatically favour granting an extension. Tribunals are entitled to consider the relative strength or weakness of the defence and assess how much weight should be attached to it.

Most importantly, the EAT emphasised that the explanation for the delay remains a critical consideration. In some cases, the absence of a satisfactory explanation, or the presentation of a false explanation, may be the decisive factor. Given the tribunal’s unchallenged findings in this case that the employer had ignored correspondence and advanced an untrue explanation, it was entitled to refuse the extension despite the serious consequences for the employer.

The Birketts view

This decision serves as an important warning to employers. While tribunals have historically taken a more flexible approach to late ET3 responses than to late presentation of claims, this case shows that there are limits to that flexibility, particularly where an employer cannot provide a credible explanation for the delay.

The most significant aspect of the judgment is the EAT’s clarification of how the Kwik Save factors interact. The decision confirms that neither prejudice nor the existence of an arguable defence will automatically justify an extension of time. Tribunals must stand back and consider all relevant factors, including the overriding objective and the efficient use of tribunal resources.

The outcome in this case turned heavily on the tribunal’s findings that correspondence had been repeatedly received and ignored, and that the explanation advanced by the employer was untrue. Employers faced with a missed ET3 deadline are therefore likely to fare much better where they acknowledge an administrative failure and provide a genuine explanation, rather than attempting to dispute facts that may later prove unsustainable.

To avoid this situation arising, employers should ensure they have robust systems in place for identifying and escalating employment tribunal correspondence received at local sites and branches. Any applications for an extension of time should be made promptly, supported with evidence to explain the delay.