The prison population in England and Wales hit a record high for the fifth consecutive week yesterday, figures showed.
The number of prisoners being held rose by 172, taking the total to 87,673, 1,014 short of the usable operational capacity, the Ministry of Justice said.
Contingency measures are being explored “should further pressure be placed on the prison estate”, but no places are currently activated under Operation Safeguard, which would see police cells used to hold prisoners, a spokeswoman said.
The record came as separate figures showed almost 3,000 people suspected of being involved in the riots in the capital alone have been arrested. At least 2,952 suspects have been arrested, with at least 1,774 charged, the Scotland Yard figures showed.
Those involved in the riots have been jailed for an average of 10.4 months for violent disorder, compared with an average of 5.3 months last year, the latest Ministry figures showed.
A Prison Service spokeswoman added: “We have seen a significant rise in the prison population as a result of the public disorder in August.
“Managing the increase in the population is challenging but we have been continually developing contingencies to manage the additional population.”