Section 20. Date on which pre-emptor's right accrues

A person who has obtained a decree for pre-emption in respect of any property shall acquire no title to that property until he pays into court the sum of money required to be paid in accordance with the pre-emption decree, but, upon such payment being made, any alienation of the property made by the original transferee or by any person claiming through ham shall be voidable at the option of the decree-holder with effect from the date of such payment.