New construction starts in the build-to-rent (BTR) sector have collapsed by 79% year-on-year, according to the latest development data, marking one of the sharpest contractions the purpose-built rental market has experienced since it emerged as a mainstream asset class a decade ago. The figures show institutional investors and developers pulling back sharply from launching new schemes, even as rental demand across the UK continues to outstrip supply by a wide margin. For a sector that only recently attracted tens of billions of pounds in pension fund and sovereign wealth capital, the reversal is stark and carries consequences that extend well beyond the immediate construction pipeline.