Rebuttal evidence before an Advisory Board includes examining available defence witnesses; refusal can vitiate preventive detention.

A detenu has a constitutional safeguard to present oral and documentary rebuttal evidence before the Advisory Board, including examination of available defence witnesses present at the hearing. The Board may regulate its procedure and is not required to summon witnesses, but it cannot refuse a requested opportunity that would nullify the detenu's right to lead rebuttal evidence. Where the witnesses were present and the request to examine them was denied, the denial was unlawful and invalidated the continued detention.

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Issues: Whether a detenu has a right to examine witnesses in rebuttal before the Advisory Board, and whether denial of that opportunity vitiates the continued detention.

Analysis: The decision in A.K. Roy recognises a constitutional safeguard enabling the detenu to present oral and documentary evidence in rebuttal before the Advisory Board. That right is subject to the limitation that the witnesses must be kept present at the appointed time, and the Board is under no obligation to summon them. The Advisory Board may regulate its procedure, but it cannot adopt a course that nullifies the detenu's right to lead rebuttal evidence. On the facts, the witnesses were present, the request to examine them was refused, and the detenu was denied the opportunity to adduce the defence evidence he had chosen to present.

Conclusion: The denial of the opportunity to examine the witnesses was unlawful and rendered the continued detention invalid.

Ratio Decidendi: The constitutional safeguard of rebuttal evidence before an Advisory Board includes the right to examine available defence witnesses present at the hearing, and refusal of that opportunity vitiates preventive detention.

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