The Common Law recognizes the contract of guarantee as an exception to the rule of proof parol, which means that admissible evidence may be used for a contract of guarantee in order to exclude the application of the rule of proof parol. In practice, it is rare to find a warranty contract as an exception, as it must be strictly proven; and the burden of proof is facilitated only if the subject matter of the main contract is more unusual.  The rules on proof of probation do not apply to guarantee contracts, but only to primary contracts. Most warranty contracts are unilateral, which means that only one party makes a promise (for example. B the supply of a product or service) in exchange for funds. The approval of the initial contract is in return for the ancillary contract. Although the procedural judge found the existence of the oral agreement, he considered that it was inapplicable. Since the oral agreement was concluded taking into account the conclusion of each of the sales contracts by Mr Adicho and its terms were incompatible with the written terms of each of those contracts, the oral agreement was not valid. It can also be embodied as follows: a guarantee contract is a contract that induces a person to enter into a separate “primary” contract. For example, if X agrees to purchase goods from Y manufactured accordingly by Z, on the basis of Z`s assurance of the high quality of the goods, X and Z may have entered into an ancillary contract consisting of Z`s quality promise, taking into account X`s promise, the main contract with Y has been given. On appeal, the Court of Appeal upheld the procedural judge`s decision that the ancillary activity was not applicable. The Court of Appeal applied the High Court hoyts` long-standing decision against Spencer. In this case, the High Court has recognised that the mere act of a party entering into a main agreement may itself be consideration in support of an `ancillary contract` concluded on or before the conclusion of the main agreement.
This is if the common intention of the parties. it was a question of “abolishing” the old contracts by an agreement “totally new” and “concluded in itself” or “self-unsustainable”, of “repealing”, of “repealing” them, of “replacing” them or of “swearing them”, which “contained in full the old conditions, as well as those taken up by the new concepts”. Despite the close link between an ancillary contract and the so-called main contract to which it refers, the two separate contracts are applicable as such, unless the obligations set out in one of the two contracts are considered to be dependent or dependent on the performance of a corresponding obligation in the other contract. In the English case of Barry vs. Davies, it was found that an auctioneer and a buyer had entered into a warranty agreement.  It was decided that, even if the main order does not concern the auction, the advantages granted to the auction for the increase in the price of the offer constitute a good consideration.  If these conditions are met, the courts may find that an ancillary contract has been entered into and enforce the promise not under the main contract, but under a completely separate (but related) secondary contract: Graw S, An Introduction to the Law of Contract (1998), 3rd Ed, Lawbook Company Information Services, North Ryde, p. 162. . .