The UK's private rented sector is contracting at a pace that should alarm anyone hoping for relief on rents. New data confirms what letting agents across the country have been reporting anecdotally for months: landlords are exiting the market in meaningful numbers, and the properties that remain are being let faster and at higher prices than at any point in recent memory. The proximate cause is straightforward — mortgage rates that have roughly doubled or trebled since the low-rate era ending in 2022 have turned marginal buy-to-let investments into loss-making propositions, and a wave of landlords holding fixed-rate deals from 2019 to 2021 are now refinancing into a starkly different arithmetic.