When a vendor contracts to sell to a purchaser an agreement for a lease and the purchaser subsequently repudiates the contract, can the vendor continue to exercise its right to exercise that right?

In Brewer v. Broadwood (1883), L.R. 22 Ch. D, p. 105, 52 L.J. Ch. 136, 47 L.T. 508, a vendor contracted to sell to a purchaser an agreement for a lease, and the purchaser afterwards repudiated the contract. At the date of the agreement and of the repudiation, the agreement to lease was voidable at the will of a third party. This third party was not taking any steps to avoid the agreement to lease, and was even willing to confirm it on certain conditions. It was, nevertheless, held that the purchaser was entitled to repudiate the contract. Fry, J., in the course of his judgment, after citing the above quotation from Forrer v. Nash, said: “That principle has, of course, nothing whatever to do with cases in which there are outstanding interests which the vendor has the power of gathering in, because in that case he is able and he is under an obligation to get them in; but it has a great deal to do with a case in which the only title of the vendor is contingent upon the will and volition of a third person.”