There was an increase of 841,231 in the number of privately rented or rent free houses in England and Wales between 2011 and 2021. A smaller rise than from 2001 to 2011. According to the BPF there are currently 73,739 BTR homes in the whole UK with a further 47,764 under construction and 115,859 in planning. The BTR figures were virtually nil in 2011. Plenty of scope therefore for significantly more growth in the BTR sector in the next decade.

https://www.ons.gov.uk/peoplepopulationandcommunity/housing/bulletins/housingenglandandwales/census2021