In an application to set aside an adopted and implemented business rescue plan, creditors who voted for the plan and who have received payments under it must be joined as parties because they have a direct and substantial interest in the subject matter of the litigation. Their interest would be necessarily prejudiced if the plan were set aside without their participation, as they would lose the benefit of their vote, would cease to receive anticipated payments, would have to repay amounts already received, and might face significantly reduced dividends in the event of liquidation. The test for non-joinder is whether a party has a direct and substantial interest in the subject matter of the litigation which may prejudice the party that has not been joined; if an order or judgment cannot be sustained without necessarily prejudicing the interests of third parties that have not been joined, then those third parties have a legal interest in the matter and must be joined. Notice given to affected parties pursuant to s 130 of the Companies Act 71 of 2008 is insufficient to cure non-joinder, as such notice provisions are confined to applications brought prior to adoption of a business rescue plan. Furthermore, a party's non-intervention after receipt of notice of legal proceedings, short of a citation, cannot be treated as a representation that the party will submit to and be bound by any judgment that may be given.