Ethekwini Municipality v Verulam Medicentre (Pty) Ltd

In 1993 the Ethekwini Municipality (then a town council) sold immovable property to Verulam Medicentre (Pty) Ltd under a written sale agreement, with the purchase price payable by deposit and instalments bearing interest. The municipality failed to comply with statutory requirements under the Local Authorities Ordinance Act 25 of 1974, rendering the agreement invalid. By 1996 the respondent had paid R1 141 153,48. In 1999 the parties concluded a second agreement renegotiating the sale at a higher price, crediting only the capital previously paid, and making transfer conditional on successful rezoning. Clause 12.7 provided that if rezoning failed and the purchaser cancelled, all amounts paid would be refunded with interest at 15,5% per annum compounded monthly from date of payment. Rezoning was refused in 2002, the respondent cancelled, and claimed repayment of the capital plus accumulated interest exceeding the capital. The municipality contended that the claim was limited by the in duplum rule.

The appeal was dismissed with costs, including the costs of two counsel.

The case authoritatively clarifies that the in duplum rule in South African law applies only to arrear interest on an existing debt and not to interest-like amounts agreed as part of a restitutionary or pricing mechanism. It reinforces a contextual, purposive approach to contractual interpretation and limits attempts to invoke the in duplum rule outside its established scope.