At the end of paragraph (b) of the proviso to subsection (2) of section ninety-nine of the Army Act, 1955, and of paragraph (b) of the proviso to subsection (2) of section ninety-nine of the Air Force Act, 1955 (by virtue of which provisos the admission in evidence in proceedings before a court-martial of a statutory declaration put forward by the defence is prohibited unless a copy thereof has, not less than seven days before the trial, been served on the commanding officer of the accused) there shall be added the words " or the commanding officer of the accused has given his agreement in writing to its admission ".