The prison population in England and Wales has hit an all-time high of 80,303, figures show.
There are now record numbers of inmates.
The total number of inmates rose by 100 overnight from the previous record, which was set on Thursday.
Prison Service bosses have been forced to start using court cells to hold some inmates as police cells near capacity.
The Lord Chancellor, who will soon take over responsibility for prisons, has refused to rule out early release schemes to ease overcrowding.
On Friday, prison sources told the BBC that the population in England and Wales had reached 80,303, including 384 held in police cells as part of the emergency Operation Safeguard back-up plan.
On Thursday, numbers had reached 80,199, forcing the Home Office to call on courts to provide overnight accommodation for inmates.
The BBC understands that four prisoners were held overnight at Highbury Magistrates Court earlier in the week and one of them attempted suicide.
The record numbers came the day after the prime minister confirmed that the Home Office would be split, with responsibilities for prisons and offenders passing to a new ministry of justice.
Lord Falconer, the Lord Chancellor, will take on prisons along with the courts currently run by the Department for Constitutional Affairs.
Responding to the record numbers, Lord Falconer refused to rule out an early release scheme once the new department begins work in May.
He also refused to rule out requiring judges to take account of prison capacity when sentencing, but that would require legislation. "Decisions about prison population remain for [Home Secretary] Dr Reid until May 9," said Lord Falconer.
"I'm not saying anything in detail about what policy will be in relation to prisons until I become Secretary of State for Justice on May 9.
"The current position is it is not for the judges to take into account what resources there are [in terms of prison places].
"If that were to become the case then I think that it would have to be dealt with by legislation. In relation to policy like that we need to look at it after May 9."
In a statement after the announcement of the new ministry, the top judge in England and Wales, Lord Phillips, warned that there needed to be more public debate about prison overcrowding.
"The judiciary are of the view that any changes to the present arrangements will, in due course, require legislation," said the Lord Chief Justice.
"Without this debate there is a risk that the new ministry will be faced with a situation of recurrent crisis, or judges will be placed under pressure to impose sentences that they do not believe are appropriate."
Home Secretary John Reid has announced plans to build two new prisons in Merseyside and London as part of a plan to provide an extra 8,000 places - but critics say this may not be enough at current rates.