Union Bank of Nigeria Ltd. v. Professor Albert Ojo Ozigi (1994)

Background & Parties

This appeal before the Supreme Court arose from a dispute between Union Bank of Nigeria Ltd. (the Appellant), a commercial bank, and one of its customers, Professor Albert Ojo Ozigi (the Respondent). The central legal problem concerned the power of a bank to unilaterally vary the interest rate on a loan facility where the foundational contract, a deed of mortgage, did not explicitly state a fixed rate but allowed the bank to stipulate the rate 'from time to time'. This case scrutinizes the delicate balance between the express terms of a written contract and the admissibility of extrinsic parol evidence to interpret or vary those terms, particularly in a banker-customer relationship.

Material Facts

• In 1982, the Respondent obtained a loan of N250,000.00 from the Appellant to complete a restaurant project in Ilorin.
• The loan was secured by two deeds of mortgage which stipulated that interest would be charged at a rate to be determined by the bank from time to time.
• A disagreement arose in 1988 regarding the applicable interest rate. The Respondent contended that a fixed rate of 11% per annum was agreed upon during oral negotiations with the bank's Assistant General Manager prior to the execution of the mortgage deeds.
• The Appellant argued that the rate was not fixed and that it had the contractual right, which it exercised, to vary the interest rates in line with Central Bank of Nigeria (CBN) credit guidelines. This resulted in a significantly higher outstanding balance than the Respondent's calculation.
• The Respondent instituted an action at the Kwara State High Court, seeking declarations that the bank could not unilaterally increase the interest rate without his consent.
• The trial court and the Court of Appeal both found in favour of the Respondent, holding that the bank could not unilaterally alter the interest rate and admitting the Respondent's oral evidence of an 11% fixed rate.

Real Issue

The core tension in this case was whether the sanctity of a written agreement, which appears to grant a bank discretionary power to set interest rates, can be overridden by prior oral agreements. It questions whether a clause allowing a party to stipulate terms 'from time to time' amounts to an unfettered right or if it is constrained by the initial consensus of the parties, thereby testing the limits of the parol evidence rule.

Legal Issues

The Supreme Court was tasked with resolving whether the lower courts erred in law by admitting and relying on extrinsic oral evidence to vary the terms of the written mortgage deeds, particularly concerning the interest rate chargeable on the loan facility.

Court's Analysis

The Supreme Court, led by Adio, JSC, engaged in a meticulous analysis of the parol evidence rule. The Court emphasized that where parties have deliberately embodied their agreement in a written document, extrinsic evidence is inadmissible to add to, vary, subtract from, or contradict the terms of that document. The lower courts had accepted the Respondent's oral testimony of an 11% fixed rate, thereby modifying the written terms of the mortgage deeds. The Supreme Court found this to be a fundamental error. It held that the phrase allowing the bank to stipulate the rate 'from time to time' was clear and unambiguous. To allow oral evidence to substitute a fixed rate for this clear term would be to undermine the very foundation of written contracts. The Court reasoned that the purpose of reducing agreements to writing is to achieve certainty and finality. The lower courts' decisions created a dangerous precedent where the explicit terms of a commercial instrument could be easily undone by subsequent, and often unverifiable, oral claims. The Supreme Court sacrificed the perceived fairness to the individual borrower on these specific facts to uphold the paramount legal principle of the sanctity of written contracts, which is crucial for commercial stability.

Decision & Outcome

The Supreme Court allowed the appeal, setting aside the judgments of the trial court and the Court of Appeal. The Court held that the Appellant, Union Bank, was entitled to vary the interest rate as stipulated in the mortgage deeds and in accordance with the prevailing CBN guidelines.

Ratio Decidendi

Where a written contract, such as a mortgage deed, contains a clear and unambiguous clause allowing a bank to stipulate the interest rate on a facility 'from time to time', extrinsic parol evidence of a prior oral agreement for a different (e.g., fixed) interest rate is inadmissible to contradict, alter, or vary the express written term.

Significance

The judgment in Union Bank v. Ozigi stands as a powerful reaffirmation of the parol evidence rule in Nigerian contract law. It clarifies that a bank's right to vary interest rates, when expressly provided for in a loan agreement, is a valid exercise of its contractual power. The decision establishes that such a clause is not ambiguous and does not require the customer's subsequent consent for each variation, provided the variations are in line with regulatory guidelines. This case has become a cornerstone precedent in banking and commercial litigation, reinforcing the principle that parties are bound by the terms of the agreements they sign and limiting the scope for parties to escape their obligations through claims of contradictory oral agreements.