The mortgagee Devi Sahai defended the suit on diverse grounds but the principal and the only defence canvassed was one under section 53A of the Act, namely, that even though the sale deed purporting to sell equity of redemption having not been registered would not clothe the mortgagee with title of owner to the mortgaged property, yet he could defend his possession as transferee owner under the doctrine of part performance in as much as not only is the mortgagee in possession in part performance of the contract of sale but has continued in possession in part perfor 193 mance of the contract and has done several acts unequivocally referable or attributable to the contract and that the mortgage as transferee has not only performed but is willing to perform his part of the contract and, therefore, the mortgagor is debarred from enforcing against the mortgagee any right in respect of the mortgaged property.