New DElhi, June 27 -- The Supreme Court has ruled that appellate courts can increase a sentence in an accused's own appeal if the punishment awarded by the trial court was illegal and fell below the minimum prescribed by law. In a judgment released on Thursday, a bench of justices BV Nagarathna and Ujjal Bhuyan upheld a Sikkim High Court decision that increased the sentence of two men convicted of gang rape from 12 years to 20 years imprisonment, even though the enhancement occurred while deciding appeals filed by the convicts themselves. The court clarified that such an exercise does not amount to an impermissible enhancement of sentence under appellate powers. Rather, it is a correction of an illegal sentence that was contrary to a statutory mandate. "The accused has a right to challenge his conviction, but he has no right to insist upon the continuance of an illegal sentence," held the bench. The judgment clarifies an important aspect of criminal appellate jurisprudence. While courts generally cannot enhance punishment in an appeal filed solely by a convict, they can intervene where the original sentence itself is illegal because it violates a mandatory statutory minimum. In such cases, the Supreme Court has now held, correcting the sentence is not an enhancement of punishment but a judicial obligation to enforce the law. The ruling came in appeals filed by Karan Chettri and another convict who were found guilty of gang rape under IPC Section 376D for sexually assaulting a 52-year-old woman in Sikkim in 2021. A trial court had sentenced them to 12 years' rigorous imprisonment. However, Section 376D prescribes a minimum punishment of 20 years, extendable to imprisonment for the remainder of a person's natural life. When the convicts challenged their conviction before the Sikkim High Court, the high court upheld the conviction under Section 376D and, exercising suo motu revisional powers, increased the sentence to the statutory minimum of 20 years. Before the Supreme Court, the convicts argued that Section 386(b)(iii) of the Code of Criminal Procedure expressly prohibits an appellate court from enhancing a sentence in an appeal filed by an accused. The bench acknowledged the contention. However, it held that the present case stood on a fundamentally different footing as the trial court's sentence was contrary to law. Justice Nagarathna observed that the trial court had committed a "gross defect" by imposing a punishment lower than the minimum sentence prescribed by Parliament for gang rape. The judgment drew a distinction between a sentence that may be considered inadequate and one that is outright illegal because it disregards a mandatory statutory minimum. "The appellate court, by raising the sentence to the statutory minimum, is not making the sentence harsher...but is merely giving effect to what the law compulsorily required from the outset," it said. Upholding the HC decision, the SC concluded that replacing the 12-year sentence with the mandatory minimum of 20 years was a lawful exercise aimed at restoring legality to the sentencing process and ensuring compliance with Parliament's command under Section 376D....