IEA Section 144

Any witness may be asked, whilst under examination whether any contract, grant or other disposition of property, as to which he is giving evidence, was not contained in a document, and if he says that it was, or if he is about to make any statement as to the contents of any document, which in the opinion of the Court, ought to be produced, the adverse party may object to such evidence being given until such document is produced, or until facts have been proved which entitle the party who called the witness to give secondary evidence of it.