Prisoners will be temporarily held in police cells to deal with prisons running out of space, the Ministry of Justice (MoJ) has confirmed.
The emergency measures, called Operation Safeguard, are triggered when prisons are close to capacity.
The government says 200 cells will be freed up by the measures, which are expected to last for two months but could be extended depending on the size of the prison population.
The announcement comes just days before a new prison near York is scheduled to open. HMP Millsike will create 1500 new spaces that the government hopes will reduce pressure on the criminal justice system.
While the system is close to full capacity, the MoJ says there is still space.
Figures released on Monday show the number of prisoners is at a six-month high, with 87,556 people currently in custody.
This is not the first time Operation Safeguard has been triggered.
