Justice Navin Sinha held that procedure u/s 313 CrPC may very well be considered as a fundamental right as part of Rights available under Article 21 of the Constitution.
From Para 16,
16. Section 313, Cr.P.C. cannot be seen simply as a part of audi alteram partem. It confers a valuable right upon an accused to establish his innocence and can well be considered beyond a statutory right as a constitutional right to a fair trial under Article 21 of the Constitution, even if it is not to be considered as a piece of substantive evidence, not being on oath under Section 313(2), Cr.P.C. The importance of this right has been considered time and again by this court, but it yet remains to be applied in practice as we shall see presently in the discussion to follow. If the accused takes a defence after the prosecution evidence is closed, under Section 313(1)(b) Cr.P.C. the Court is duty bound under Section 313(4) Cr.P.C. to consider the same. The mere use of the word ‘may’ cannot be held to confer a discretionary power on the court to consider or not to consider such defence, since it constitutes a valuable right of an accused for access to justice, and the likelihood of the prejudice that may be caused thereby. Whether the defence is acceptable or not and whether it is compatible or incompatible with the evidence available is an entirely different matter. If there has been no consideration at all of the defence taken under Section 313 Cr.P.C., in the given facts of a case, the conviction may well stand vitiated. To our mind, a solemn duty is cast on the court in dispensation of justice to adequately consider the defence of the accused taken under Section 313 Cr.P.C. and to either accept or reject the same for reasons specified in writing.
Citations : 2018 SCC ONLINE SC 2281, 2019 (1) AICLR 192 (SC), 2018 (3) JIC 75 (SC), AIR 2018 SC 5361
Other Sources:
https://indiankanoon.org/doc/152892250/
https://www.casemine.com/judgement/in/5bd9d9c99eff430a1b47fd8c
