A 90% decrease in the number of NHS psychiatric beds has contributed to a trebling of the total prison population, concludes a new study.
Scientists at Newcastle University found between 1960 and 2019 the number of psychiatric beds reduced by 93%.
Over the same period, the prison population increased by 208%, and the number of female prisoners more than quadrupled.
The research, published in the British Journal of Psychiatry, is the first to analyse almost 60 years of annual data on NHS bed numbers and the prison population in England using time lag analysis.
Experts say the NHS needs to better integrate health services, social care, housing and employment support to break the link between community care and rising rates of imprisonment.
Dr Patrick Keown, Honorary Clinical Senior Lecturer at Newcastle University, said: “Our study shows that as the number of psychiatric NHS beds available was reduced, then in subsequent years we saw a growth in the size of the prison population.
"We show that cuts in the number of psychiatric beds is associated with more prisoners 10 years later, and this was true for the whole period of 1960 to 2019.
"For every 100 psychiatric beds that were closed, there were 36 more prisoners 10 years later – three more female prisoners and 33 more male prisoners.
The relationship between NHS psychiatric beds and prison numbers, known as the ‘Penrose hypothesis’, was first proposed in 1939 and subsequently reported in several countries.
Between 1960 and 2019
The research by scientists at Newcastle and Sheffield universities acknowledges the reasons behind the increase in prison numbers are complex and multi-factorial.
The researchers found it was also notable that there was a very strong association between reductions in beds for people with intellectual disability and the increase in the prison population.
Dr Iain McKinnon, Honorary Clinical Senior Lecturer at Newcastle University, said: “We believe that further bed closures, especially secure beds for offenders including those with intellectual and developmental disabilities, and the proposed changes to mental health legislation should be very carefully considered.