It is hereby declared that the Deceased Brother's Widow's Marriage Act, 1921, applies to Northern Ireland, and the said Act shall be deemed to have applied to Northern Ireland as from the passing thereof:
Provided that in case, on or after the twenty-eighth day of July, nineteen hundred and twenty-one and before the passing of this Act, a marriage contracted between a man and his deceased brother's widow shall have been annulled, or either party to such marriage shall have contracted a further marriage during the lifetime of the other party which would have been lawful except for such former marriage, such former marriage shall be deemed to have become and to be void upon and after the day upon which it was so annulled, or upon which either party thereto contracted a further marriage as aforesaid, and the validity of such further marriage shall not be affected by such former marriage.