Where there is flagrant and substantial non-compliance with court rules for filing the record of appeal, and the explanation for such non-compliance is manifestly inadequate with multiple unexplained periods of delay, condonation will be refused without consideration of prospects of success. The interests of justice, which form the touchstone for condonation applications, require consideration of multiple factors including the extent and cause of delay, the reasonableness of the explanation, the effect on administration of justice, and the interests of the other party. An applicant seeking condonation must provide a full, detailed and accurate explanation covering the entire period of delay. Unexplained gaps in the chronology are fatal to the application. Where an appeal record is incomplete and lacks essential evidence, the court cannot properly consider the appeal on its merits, providing an additional ground for refusing condonation. In matters concerning children, the child's best interests are paramount under section 28(2) of the Constitution, and delay in finalizing litigation concerning a disabled child's compensation claim weighs significantly against granting condonation.