There are times where a witness whose evidence is every important in determining a case may deliberately refuse to come to court and testify for reasons best known to him. Of course, this can be very frustrating. However, the appearance of such witness can be secured where he or she is mandated or compelled to appear before the court on a stated date via a writ of court known as subpoena ducestecum a witness is ordered to produce a specified document while by a subpoena ad testificandum the witness is ordered to appear and give testimony. A subpoena is an Order of court, disobedience of which carries serious penalty as in every order of court.
See Omidiran V. Etteh (2011) 2 NWLR (Pt. 1232) 471 @ 500; Akintayo V. Jolaoye (2013) All FWLR (Pt. 679) 1172 – 1173.