Companies Act 1948

15 The directors may from time to time make calls upon the members in respect of any moneys unpaid on their shares (whether on account of the nominal value of the shares or by way of premium) and not by the conditions of allotment thereof made payable at fixed times, provided that no call shall exceed one-fourth of the nominal value of the share or be payable at less than one month from the date fixed for the payment of the last preceding call, and each member shall (subject to receiving at least fourteen days' notice specifying the time or times and place of payment) pay to the company at the time or times, and place so specified the amount called on his shares. A call may be revoked or postponed as the directors may determine.