the new investment market for build-to-rent properties to extensively develop. Altogether these different kinds of involvement have created a rather complex spectrum within the private rental sector. Decline in property investment from 2017 Following changes to the taxation of landlords, with Section 24 of the Finance Act 2015, that came into effect in April 2017, the private rented sector therefore peaked at 2.88 million households and began to steadily shrink. The introduction of Section 24 removed the right of the landlord to deduct mortgage interest and other finance costs, which included mortgage arrangement fees, from their rental income before calculating their Income Tax liability, to Her Majesty's Revenue & Customs (HMRC). In August 2018, the Royal Institution of Chartered Surveyors warned that smaller BTL landlords were being pushed out of the UK housing market by the removal of mortgage interest tax relief, stricter lending criteria, and higher Stamp Duty Land Tax (SDLT), and that rents would need to rise by some 15 percent. By 2019, the total number of dwellings in the private rented sector had fallen by 222,570, reaching its lowest level since December 2012, when the total had been 2.58 million. As a result, three landlord associations urged the government to take action to reverse this trend. References Housing in the United Kingdom