The Negotiable Instruments Act, 1881
§121 — Estoppel against denying capacity of payee to indorse
No maker of a promissory note and no acceptor of a bill of exchange [payable to order] shall, in a suit thereon by a holder in due course, be permitted to deny the payee's capacity, at the date of the note or bill, to indorse the same. Subs. by Act 66 of 1988, s. 3, for “six per centum” (w.e.f . 30 of 1919, s. 5, for “payable to, or to the order of, a specified person”.