Those who have bought and sold real property would be aware that at 'settlement' the buyer pays the purchase price and in exchange, they receive the clear title to the land. Clear title means that any mortgage over the property is released. To release the mortgage, the seller's mortgagee will need to be paid out. Usually, all this happens in one place at the same time. While it looks like a single seamless transaction, in fact it involves two discrete transactions: that between the outgoing mortgagee and the seller; and that between the seller and the buyer.
A 2012 decision of the Full Court of the Federal Court has called into question the position of hte releasing mortgagee at settlement through the operation of a tax statute.