The Patents Act,1970
Section 147. Evidence of entries, documents, etc.
(1) A certificate purporting to be signed by the Controller as to any entry, matter or thing which he is authorised by this Act or any rules made thereunder to make or do, shall be prima facie evidence of the entry having been made and of the contents thereof and of the matter or thing having been done or omitted to be done.
(2) A copy of any entry in any register or of any document kept in the patent office or of any patent, or an extract from any such register or document, purporting to be certified by the Controller and sealed with the seal of the patent office shall be admitted in evidence in all courts, and in all proceedings, without further proof or production of the original.
(3) The Controller or any other officer of the patent office shall not, in any legal proceedings to which he is not a party, be compellable to produce the register or any other document in his custody, the contents of which can be proved by the production of a certified copy issued under this Act or to appear as a witness to prove the matters therein recorded unless by order of the court made for special causes.