Para 289A(iv) of the Immigration Rules HC 395 gave a caseworker discretion to decide what evidence to require an applicant to produce in the particular case. In exercising that discretion it would be usual to apply guidance given in section 4 of Chapter 8 of the Immigration Directorate Instructions (IDIs); but if that were not possible the applicant should be given the chance to produce such other relevant evidence as he or she might wish.