NNB Generation Company (HPC) Limited v The Commissioners for HMRC

Decision date: 26 February 2026

Neutral citation: [2026] UKFTT 316 (TC)

Overall AI summary confidence: high

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Short overview

This short overview is intended to summarise the case, issues and outcome so far as they are supported by the judgment.

AI confidence in this short overview: high

NNB sought re-categorisation of its appeal against an HMRC information notice from "standard" to "complex" and sought sequential exchange of witness statements. The First-tier Tribunal held that none of the Rule 23(4) thresholds (length/complexity of evidence or hearing; complex/important issue; large financial sum) were satisfied and refused re-categorisation; it also refused sequential exchange, keeping simultaneous exchange by 27 February 2026 subject to leave to renew with any extension application.

Ratio decidendi

This summary is intended to identify the ratio decidendi, meaning the legal reasons for deciding and the binding part of the decision.

AI confidence in this ratio decidendi summary: high

The Tribunal applied Rule 23(4) by reference to the spectrum of cases typically heard by the Tax Tribunal (not by reference to the subject-matter type alone) and held that meeting a Rule 23(4) threshold is a necessary but not sufficient condition for allocation as "complex": the Tribunal must then exercise its discretion holistically, guided by the overriding objective and proportionality, before allocating a case to the complex category.

Obiter dicta

This summary is intended to identify obiter dicta, meaning observations made by the way that were not necessary to deciding the case and are not binding.

AI confidence in this obiter dicta summary: medium

The judgment observed that substantive complexity of the underlying dispute (for example, R&D issues in nuclear reactor design) does not automatically make an information-notice appeal "complex" for categorisation purposes, and that the Tribunal can often determine whether information is "reasonably required" using summaries and a general understanding, leaving detailed granular analysis only where proportionality requires it.