Per Lord Cairns LC in Cundy v Lindsay (1878) 3 App Cas 459, House of Lords:
…the purchaser of a chattel takes the chattel as a general rule subject to what may turn out to be certain infirmities in the title. If he purchases the chattel in market overt, he obtains a title which is good against all the world; but if he does not purchase the chattel in market overt, and if it turns out that the chattel has been found by the person who professed to sell it, the purchaser will not obtain a title good as against the real owner. If it turns out that the chattel has been stolen by the person who has professed to sell it, the purchaser will not obtain a title. If it turns out that the chattel has come into the hands of the person who professed to sell it, by a de facto contract, that is to say, a contract which has purported to pass the property to him from the owner of the property, there the purchaser will obtain a good title, even although afterwards it should appear that there were circumstances connected with that contract, which would enable the original owner of the goods to reduce it, and to set it aside, because these circumstances so enabling the original owner of the goods, or of the chattel, to reduce the contract and to set it aside, will not be allowed to interfere with a title for valuable consideration obtained by some third party during the interval while the contract remained unreduced.
Lord Blanesburgh in Bell v Lever Bros Ltd  AC 161,  All ER Rep 1, stated that:
… the claim made by the heads of claim is for rescission of the agreements of settlement, relief properly consequent upon a case of voidability either for fraud or unilateral mistake induced by fraud. But if the allegation, even alternative, was that the agreements were entered into under mutual mistake of fact, then these agreements were not voidable but void ab initio, and no order on that footing is even hinted at in the relief sought.
Per Dixon J in McDonald v Dennys Lascelles Ltd (1933) 48 CLR 457 at 476-477:
When a party to a simple contract, upon a breach by the other contracting party of a condition of the contract, elects to treat the contract as no longer binding upon him, the contract is not rescinded as from the beginning. Both parties are discharged from the further performance of the contract, but rights are not divested or discharged which have already been unconditionally acquired. Rights and obligations which arise from the partial execution of the contract and causes of action which have accrued from its breach alike continue unaffected. When a contract is rescinded because of matters which affect its formation, as in the case of fraud, the parties are to be rehabilitated and restored, so far as may be, to the position they occupied before the contract was made. But when a contract, which is not void or voidable at law, or liable to be set aside in equity, is dissolved at the election of one party because the other has not observed an essential condition or has committed a breach going to its root, the contract is determined so far as it is executory only and the party in default is liable for damages for its breach.
Lord Denning MR in Lewis v Averay  1 QB 198, in the following words expressed his opinion on the way in which mistake as to identity affects the status of the contract:
When two parties have come to a contract—or rather what appears, on the face of it, to be a contract—the fact that one party is mistaken as to the identity of the other does not mean that there is no contract, or that the contract is a nullity and void from the beginning. It only means that the contract is voidable, that is, liable to be set aside at the instance of the mistaken person, so long as he does so before third parties have in good faith acquired rights under it.