The Secretary of State may in such cases as he thinks fit, on the application of any person with respect to whose citizenship of the United Kingdom and Colonies a doubt exists. Whether on a question of fact or of law, certify that person is a citizen of the United Kingdom and Colonies; and a certificate issued under this section shall, unless it is proved that it was obtained by means of fraud, false representation or concealment of any material fact, be conclusive evidence that person was such a citizen on the date thereof, but without prejudice to any evidence that he was such a citizen at an earlier date.
