Developer contributions provided via Section 106 agreements have become an important way to deliver affordable homes in England. In 2023–24, 44% of affordable homes were provided in this way. Developers rely on bids from registered providers of social housing (RPs) to buy the Section 106 affordable homes they deliver, but recently developers have been struggling to sell them. The Department believes this issue is widespread, despite not yet showing up in official statistics.35 This issue represents a risk to the delivery of affordable and social rent homes, and to the government’s aim of increasing overall housing supply. Additionally, developers may use unsold Section 106 affordable housing as a reason to claim financial viability issues on future development sites, as they can claim that what they previously delivered was not needed.36