Britain's private rented sector is undergoing a demographic transformation that has largely escaped mainstream attention: the number of pensioners renting rather than owning their homes is rising sharply, and landlords who fail to adapt risk being caught flat-footed by a tenant profile very different from the young professionals and families that have traditionally dominated buy-to-let portfolios. Recent figures suggest the proportion of private renters aged 65 and over has climbed from roughly 8% a decade ago to around 12% today, with some projections putting the number of retired renters above 3 million by the early 2040s. This is not a marginal trend — it is a structural realignment of who occupies Britain's 4.6 million private rental homes.