Subject to the provisions of subsection (3) of this section, a person shall not be tried under this Part of this Act for any offence unless the trial is begun within three years after the commission of the offence, disregarding any time during which he was a prisoner of war or was illegally absent.

Without prejudice to the foregoing subsection, but subject to the provisions of subsection (3) of this section, a person shall not be tried by virtue of section fifty-one of this Act for an offence committed while subject to this Act unless the trial is begun within three months after he ceased to be subject thereto.

The foregoing provisions of this section shall not apply to an offence of mutiny or desertion; and notwithstanding anything in this section a person may, with the consent of the Attorney General, be tried under this Part of this Act at any time for a civil offence within the meaning of section forty-two of this Act committed outside the United Kingdom.