The National Association of Landlords has estimated that around 440,000 landlords will suffer from the new tax rules restricting the deductions available for finance costs on their properties.  

If you follow this link, you will see that this could mean that for some landlords, especially those who spend money on maintaining their properties, the tax they have to pay will be more than the net rental income they receive.  

Time will tell whether this has an effect on the quality of the country's housing stock.