Can any person be subpoenaed as witness in a trial?
There is no property in a witness. The reason is because the court has a right to every man’s evidence. Its primary duty is to ascertain the truth. Neither one side nor the other can debar the court from ascertaining the truth either by seeing a witness beforehand or by purchasing his evidence or by making communication to him. In no way can one side prohibit the other side from seeing a witness of fact, from getting the facts from him and from calling him to give evidence or from issuing him with a subpoena: Harmony Shipping Co. S.A. v. Saudi Europe Line Ltd. [1979] 1 WLR 1380 (CA) at 1385-1386.