Guarantor liability: statutory demand converts guarantor into an assessee, enabling Second Schedule tax recovery on non payment. Where a guarantor has agreed an on demand obligation co extensive with the principal debtor's liability, the Income tax Officer must make a statutory demand; after such demand the guarantor is treated as an assessee, and if he fails to pay the Income tax Officer may initiate recovery under the Second Schedule as if the guarantor were the defaulter, with the Tax Recovery Officer empowered to take coercive measures under the guarantee bond.