Hi Raj
Generally, in relation to documents intended to be adduced as evidence, the court will ask whether the evidence, (in your case, the letter referred to) that you are trying to introduce as evidence is relevant in deciding the issue before it. If the court finds that the evidence intended to be adduced is not relevant, it will be inadmissable.
During the application proceedings for a case to be heard by a court, the rules of disclosure apply to each party & their solicitors. This generally means that each party discloses documents relevant to the issue in dispute. In addition a court can order (if it believes that the document may be relevant to the issue) by subpoena, disclosure of documents depending on the complexity & nature of the case. This rule may not always include all documents though & is dependent upon each individual client's case.
Contact a lawyer for more specific advice in relation to your specific circumstances.
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