In any legal proceeding before the SSS or in which the United States (including any Federal agency or officer of the United States) is a party:

(a) The SSS GC shall arrange for an employee to testify as a witness for the United States whenever the attorney representing the United States requests it.

(b) SSS personnel may testify for the United States both as to facts within their personal knowledge and as an expert or opinion witness. Except as provided in paragraph (c) of this section, SSS personnel may not testify as an expert or opinion witness, with regard to any matter arising out of their official duties or the functions of the SSS, for any party other than the United States in any legal proceeding in which the United States is a party. SSS personnel who receive a demand to testify on behalf of a party other than the United States may testify as to facts within the employee's personal knowledge, provided that the testimony be subject to the prior written approval of the SSS GC or other SSS legal advisor and to the Federal Rules of Civil Procedure and any applicable claims of privilege, the anticipated testimony is not adverse to the interests of the SSS or the United States Government, and is presented at no cost to the Government.

(c) SSS personnel may testify as an expert or opinion witness on behalf of the SSS or in any legal proceeding conducted by the SSS or the United States.