Where the principal officer or the trustee of the trust or the institution and the trust or the institution fails to pay the whole or any part of the tax on the accreted income referred to in sub-section (1) of section 115TD, within the time allowed under sub-section (5) of that section, he or it shall be liable to pay simple interest at the rate of one per cent for every month or part thereof on the amount of such tax for the period beginning on the date immediately after the last date on which such tax was payable and ending with the date on which the tax is actually paid.