Where the principal officer of the domestic company and the company fails to pay the whole or any part of the tax on the distributed income referred to in sub-section (1) of section 115QA, within the time allowed under sub-section (3) 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.