Section 121 of The Negotiable Instruments Act : Estoppel against denying capacity of payee to indorse.

Estoppel against denying capacity of payee to indorse. Negotiable Instruments Act 1881
No maker of a promissory note and no acceptor of a bill of exchange 1[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.1. Subs. by Act 8 of 1919, s. 5, for payable to, or to the orderof, a specified person.