The increased cost to the Exchequer of mortgage interest tax relief arising from an increase in interest rates would depend on a variety of factors, including the numbers of mortgages affected, the rate of relief applying to those mortgages and the extent to which additional relief would arise within the current ceilings. Accordingly, it is not possible to provide an accurate estimate of the potential cost.
The cost to the Exchequer of mortgage interest relief by way of tax relief at source for 2009 is estimated to be in the region of €485 million.