recruit and retain staff, and increased levels of homelessness". Despite an added 244,000 homes to England's housing stock in 2019/20, the notion that an increased supply of housing will improve affordability has been challenged: the UK Housing Review (September 2017) states, "Indeed as the evidence to the Redfern Review from Oxford Economics reminds us, it is unlikely to bring house prices down except in the very long term and with sustained high output of new homes relative to household growth. Even boosting (UK) housing supply to 310,000 homes per annum in their model only brings a five per cent fall in the baseline forecast of house prices". Therefore, the National Housing Federation (NHF) and Crisis from Heriot-Watt University argue that alongside the needed 340,000 new homes each year (until 2031), 145,000 of those “must be affordable homes”. Other factors impacting on affordability Council Tax The Joseph Rowntree Foundation has suggested replacing the current Council tax system based on bands of house prices with a system that would mean the tax was more closely related to property prices. This would increase taxes on the highest-priced properties and decrease them for the lowest. They claim it would also have the effect of reducing house price volatility. Land value tax is suggested by some as a replacement for council tax; it would be based entirely on land (i.e. location) value and not on the value of buildings built on a piece of land or improvements made. International investment demand In 2015, the Bow Group, a conservative think-tank, produced a report suggesting a reduction in international investment demand of property. The report proposed limiting foreign residents to the purchase of single new-build properties, with penalties if sold within five years. In 2016, London mayor Sadiq Khan launched an inquiry into housing costs in the city, also highlighting the impact of foreign investment. Second home ownership The government set up a £60 million fund to help councils deal with high levels of second home ownership. In 2016, a referendum in St Ives, Cornwall found 83.2% of voters in favour of new housing projects being reserved for full-time residents, as many tourists frequent the area and Cornwall is popular for second home and holiday property ownership. Buy-to-let tax changes From April 2016, a Stamp Duty surcharge of three per cent of the purchase price was required for those buying to let. From April 2017, buy-to-let mortgage