AIB Group (UK) Plc v. Martin and Another

Factual and Procedural Background

The Respondent, a banking institution, employed a standard-form mortgage deed when lending to the Appellant and the Defendant, who were business partners. Under that deed, fourteen jointly-owned properties were charged as security for both joint and individual borrowings. Separate individual mortgages were executed at the same time. When the lending facilities were later called in, the Respondent sold the secured properties but a shortfall remained. Relying on clause 2 of the joint mortgage, the Respondent sued the Appellant for the Defendant’s individual debts as well as the joint debts.

The trial judge (Judge Jacobs) held that clause 2 clearly imposed such liability; a non est factum defence failed. The Court of Appeal (Judge Morritt, with Judges Sedley and others concurring) affirmed. The Appellant obtained leave to appeal to the House of Lords (now the Supreme Court), arguing that the lower courts had misconstrued the clause.

Legal Issues Presented

1. Whether the interpretation clause in the standard mortgage deed could be applied “distributively” so that each mortgagor was liable only for debts advanced to him personally, thereby preventing the Respondent from recovering the Defendant’s separate debts from the Appellant.
2. More broadly, the proper approach to construing definition or interpretation clauses in standard-form security documents—specifically, whether such clauses may expand substantive obligations beyond the operative words of the deed.

Arguments of the Parties

Appellant's Arguments

• The phrase “the mortgagor,” which the interpretation clause states may refer to “all and/or any one” of two persons, should be read reddendo singula singulis: each singular obligation is to be matched to the relevant singular debtor.
• Construed distributively, clause 2 would create (a) a joint and several covenant for joint debts and (b) separate several covenants for each mortgagor’s individual debts, but not a cross-guarantee.
• Where two competing constructions are available, the court should prefer the one that accords with the factual matrix; there was no commercial reason for the Appellant to guarantee the Defendant’s separate borrowing.

Respondent's Arguments

• The deed contains a single covenant of “the mortgagor,” expressly declared to be joint and several; the interpretation clause therefore makes both mortgagors primarily liable for “all sums … advanced to the mortgagor,” whether advanced to them jointly or to either of them.
• The distributive reading fractures the single covenant into multiple covenants without textual warrant and leads to anomalies, e.g., leaving the Appellant liable for recovery costs (clause 2(3)) while not liable for the underlying debt.
• Standard banking documentation commonly uses interpretation clauses to achieve cross-liability; certainty in lending practice requires the court to give effect to the plain words.

Table of Precedents Cited

Court's Reasoning and Analysis

All five Law Lords dismissed the appeal, though Judge Millett dissented in principle.

• Nature of the Covenant: Judge Scott (with Judges Hutton and Rodger agreeing) held that clause 2 contains a single covenant by “the mortgagor,” expressly declared “joint and several.” The phrase “the mortgagor” therefore imports both mortgagors conjunctively and disjunctively, making each of them liable for debts advanced to the other.
• Rejection of the Distributive Approach: The majority considered the distributive reading illegitimate because it would contradict the express words “joint and several,” fragment the single covenant, and render clause 2(3) (costs) incoherent.
• Role of Standard Forms: Judge Millett acknowledged that interpretation clauses must not casually expand obligations, yet accepted that the literal, non-distributive reading was possible. Ultimately, he joined in the result out of deference to the unanimous view of his colleagues.
• Factual Matrix: The Court noted that the Appellant’s solicitor (Attorney Gold) understood the clause’s effect and had advised the Appellant accordingly, undermining any suggestion that the construction defeated the parties’ real intentions.

Holding and Implications

Appeal dismissed. The House of Lords affirmed the Court of Appeal’s decision that the Appellant is jointly and severally liable for the Defendant’s individual debts under clause 2 of the mortgage.

Implications: The judgment confirms that, where an interpretation clause states that obligations are “joint and several,” courts will enforce a cross-guarantee even in standard-form documents without separate surety wording. The decision reinforces commercial certainty but does not announce a new principle beyond applying established rules of deed construction.