The Prudential Assurance Company Ltd v HM Revenue and Customs

Factual and Procedural Background

This case concerns an appeal relating to the tax treatment of portfolio dividends—dividends paid on shares held as investments in foreign companies where the investor holds less than 10% voting power. The central issue is the compatibility of the UK's corporation tax system with EU law, specifically Articles 49 and 63 of the Treaty on the Functioning of the European Union (TFEU), which guarantee freedom of establishment and free movement of capital.

The Plaintiff, a UK-based insurance company ("Prudential"), initiated the claim in 2003, seeking recovery of unlawfully levied tax under a San Giorgio claim. The litigation has been protracted, involving multiple references to the Court of Justice of the European Union (CJEU), several stages of trial, and appeals including to the Supreme Court. The case has been managed under a Group Litigation Order (GLO) with complex procedural directions and multiple judgments.

The primary legal dispute concerns the UK's imputation system for foreign dividends, which was found by the CJEU to be discriminatory and unlawful because it treated foreign dividends less favorably than domestic dividends by failing to grant an adequate tax credit. The Plaintiff asserts entitlement to tax credits reflecting either the nominal or effective foreign tax rate, capped at the UK rate, and challenges the methodology used by the Defendant ("HMRC") in calculating the unlawful tax.

Legal Issues Presented

1. Whether EU law requires the UK to grant a tax credit for foreign portfolio dividends at the higher of the foreign nominal tax rate or the effective tax rate, capped at the UK corporation tax rate.
2. How to identify and quantify the unlawful advance corporation tax (ACT) paid by the Plaintiff arising from the discriminatory tax treatment.
3. Whether the Defendant's proposed pro-rating methodology for attributing unlawful ACT against unlawful corporation tax is correct.
4. Whether a defence of change of position is available to the Defendant in respect of the restitution claims.
5. Whether compound interest is recoverable on the sums unlawfully levied.
6. Whether limitation periods bar any of the Plaintiff's claims.

Arguments of the Parties

Appellant's Arguments (Plaintiff)

• The UK tax system unlawfully discriminates against foreign dividends by not granting a tax credit equivalent to the nominal or effective foreign tax rate, capped at the UK rate.
• Foreign-sourced dividends should be treated as franked investment income (FII) under UK law with an appropriate tax credit, thus reducing the Plaintiff’s ACT liability.
• The Defendant’s complex pro-rating methodology for calculating unlawful ACT is impractical, unverifiable, and inconsistent with statutory provisions.
• The change of position defence raised by the Defendant is inadequately pleaded and unsupported by evidence, and is not recognized under EU law in this context.
• The Plaintiff is entitled to compound interest on the sums unlawfully levied, consistent with domestic law and prior case law.
• The limitation period should be extended under section 32(1)(c) of the Limitation Act 1980 due to mistake, allowing recovery of unlawfully levied tax beyond six years.

Appellee's Arguments (Defendant)

• The tax credit should be limited to the actual tax paid (effective tax rate) rather than the nominal tax rate of the foreign company.
• The calculation of unlawful ACT requires tracing the original foreign income through complex group structures, justifying a pro-rating approach to attribution of unlawful ACT against corporation tax.
• The change of position defence is pleaded and should be considered, as the sums have been spent irretrievably as part of the UK’s tax revenue.
• The repayment of ACT should be attributed pro rata between lawful and unlawful tax liabilities.
• The limitation period bars claims for tax levied more than six years before the claim form was issued.

Table of Precedents Cited

Court's Reasoning and Analysis

The court undertook a detailed analysis of the interaction between UK corporation tax law and EU law principles, focusing on the principle of equivalence and the principle of effectiveness. It reiterated that EU law prohibits discrimination between foreign and domestic dividends and requires equivalent tax treatment.

The court accepted the CJEU’s clarification that the tax credit for foreign dividends should be at least the higher of the actual tax paid or the nominal foreign tax rate, capped at the UK rate, rejecting the Defendant’s argument that only actual tax paid should be credited. This theoretical approach, although potentially unrealistic given differences between nominal and effective tax rates, is mandated by EU law to ensure equivalence.

The court found that the Plaintiff’s proposed approach to treat foreign dividends as franked investment income (FII) under UK law with corresponding tax credits was consistent with the conforming interpretation of section 231(1) of the Income and Corporation Taxes Act 1988 (ICTA), as endorsed by the Court of Appeal in prior litigation.

The Defendant’s alternative pro-rating methodology for calculating unlawful ACT was rejected as overly complex, impractical, and inconsistent with statutory provisions. The court held that the pro-rating approach for attributing unlawful ACT against corporation tax was correct in principle but disagreed with the Defendant’s application of it in certain sub-issues, favoring a fair pro-rata attribution instead of prioritizing lawful tax.

Regarding the change of position defence, the court held that mere spending of tax revenue does not constitute a viable defence without evidential support, and that such a defence is not available under EU law in the context of San Giorgio claims for unlawful tax recovery.

On interest, the court affirmed the availability of compound interest on unlawful tax repayments, following binding Court of Appeal authority.

On limitation, the court accepted that the Plaintiff could rely on an extension of the limitation period under section 32(1)(c) of the Limitation Act 1980 due to mistake, particularly since the Defendant did not plead or prove earlier discoverability of the mistake.

Procedurally, the court criticized the inadequate and general pleadings by both parties, emphasizing the necessity of clear pleadings to define issues, prepare evidence, and ensure fair trials. The court excluded several late-raised or unpleaded issues from the appeal, reinforcing the principle that issues must be raised at trial or with permission for appeal.

Holding and Implications

The court's final decision was to ALLOW THE APPEAL IN PART AND DISMISS IT IN PART. Specifically, the appeal was allowed on the limited issues concerning the methodology for attributing unlawful ACT (Issues 21, 22, and 23), where the court favored a pro-rata approach over the Defendant’s proposed prioritization of lawful tax. Otherwise, the appeal was dismissed.

The court upheld the principle that UK legislation must be interpreted conformingly to EU law to grant tax credits for foreign dividends at the higher of nominal or effective foreign tax rates, capped at the UK rate. This confirms the unlawfulness of the UK's prior tax treatment of foreign portfolio dividends without such credits.

The ruling reinforces the requirement for clear and properly pleaded cases in complex group litigation, especially where large sums and intricate EU law principles are involved. It also clarifies the limits of procedural latitude in group litigation and the inadmissibility of late or unpleaded issues on appeal.

No new precedent was established beyond the application of existing EU law and procedural principles, but the decision has significant practical implications for the quantification of restitution claims in tax cases involving portfolio dividends and advance corporation tax.