It can also be illustrated as follows: A support contract is a contract that encourages a person to enter into a separate “primary” contract. For example, if X agrees to purchase Y products manufactured accordingly by Z, based on Z`s assurance of the high quality of the product, X and Z may consider that X and Z have entered into a guarantee agreement consisting of Z`s promise of quality, which, given X`s promise to enter into the main contract with Y , was given. , only on primary contracts. A support contract is a contract by which the contracting parties enter into or promise another contract. The two treaties are therefore linked and can be applied, even if they are not a constructive part of the original treaty.  In JJ Savage and Sons Pty Ltd v. Blakney, a mere expression of opinion was not deemed sufficient to be kept as a promise. In Crown Melbourne Limited v Cosmopolitan Hotel (Vic) Pty Ltd, a statement from a landlord to the tenants considered when negotiating a lease agreement that they are “supported during the extension” would not bind the lessor to offer another five-year lease.  A security contract, if forged between the same parties as the main contract, must not be contrary to the main contract. In other words, if the term was agreed before the formal contract was concluded (but was still in place and could not be executed before the end of the second term), the first term will remain eligible.  In essence, security contracts cannot contradict an element of the main contract or the rights that flow from it.  Main contracts and security contracts are active simultaneously and, in some cases, the provisions of these contracts may replace the provisions of the former.
For example, companies X and Y enter into a construction contract with X as the owner and Y as the owner. It then enters into a secondary contract with Z, a hardware supplier. If the materials are found to be defective, X Z can sue when they do not have a contract between them. The project must have specifically or tacitly requested the main contract and its declaration of forgiveness must have motivated the inclusion of the other party in the main contract.  According to Lord Denning MR, a support contract is considered binding “when a person gives a commitment or assurance to another who intends to react by entering into a contract.”  This rule prevents parties from changing the importance of written contracts with oral or tacit agreements that are not included in the original contract, thereby undermining their integrity. This means that, when a contract is available in writing, subsequent agreements that are not entered into in writing are not proven in a contractual dispute. There are, however, several exceptions to this rule. Consider De Lassalle v. Guildford, a loan contract case in which the latter part rented a house at the first.
The landlord promised to repair the runoff before the tenant moved in. This promise was considered by the court to be a secondary contract that allowed the tenant to sue if he found that the exits had not been fixed as promised. One theory confirms that it is possible to characterize creditworthy letters as an auxiliary contract for a third-party recipient, since letters of credit are driven by the need of the buyer and, in accordation of Jean Domat`s theory, to the cause of a letter of credit, a bank issues a credit in favour of a seller in order to exempt the buyer from his obligation to pay directly to the seller with a legal offer.