The Justice Secretary has denied UK prisons are in crisis, despite a rise in assaults by prisoners in England and Wales.
Chris Grayling's comments come as the latest surprise inspection of a facility in London found high levels of violence at the Isis prison with a high population of gang members.
Figures released last month by the Ministry of Justice showed a 6% rise in assaults in prisons in the year ending March 2014, up to 15,033 from 14,083 in the previous 12-month period.
Mr Grayling told the BBC: "We're meeting those challenges, we're recruiting more staff. I am absolutely clear there is not a crisis in our prisons".He added that prison violence "is at a lower level today than it was five years ago".
Inspectors have raised fears over high levels of violence at a prison with a high population of gang members, inspectors have warned.
In 2013, there were 254 fights and assaults at Isis prison, which holds young men aged 18 to 30, with 120 in the previous six months, Her Majesty's Inspectorate of Prisons (HMIP) said.
Many incidents were serious and some involved gangs at the prison in south-east London, HMIP said, with a higher proportion than usual involving weapons.
There were many planned assaults involving a number of inmates against a single prisoner, and some incidents were known to be gang related, inspectors added.
The Parole Board has said it may have to deal with three times as many hearings next year, following a court ruling on fairness for prisoners.
Following a ruling by the Supreme Court in October prisoners are entitled to oral hearings even if they are unlikely to be released or transferred.
This means the number of hearings could increase from 4,500 to 14,000, according to the Parole Board for England and Wales' annual report.
Two inmates have escaped from HMP Kirkham open prison in Lancashire, police have said.
Philip Stephenson, 33, who was serving a sentence for firearms offences and burglar Gareth Robinson, 24, are believed to have fled in a silver Volkswagen Golf to the Oldham area, where they are both from.
Detective Chief Inspector John Mazzolai, of Greater Manchester Police, said: "Neither of these men has been seen since they escaped from prison on Saturday.
"They are not to be approached by members of the public, but if anyone sees them or knows of their whereabouts, please contact GMP on 101 immediately or call Crimestoppers anonymously on 0800 555 111."
A 24-year-old convicted burglar has absconded from prison in Doncaster, police said.
Damian Pearson fled from HMP Hatfield in Doncaster at around 7am, South Yorkshire Police said.
Appeal to locate 24yo Damian Pearson who absconded from HMP Hatfield this morning (29/6/14) - call 101 with info http://t.co/W1zKXHKFtJ
Mr Pearson was sentenced to three-and-a-half years in prison for burglary in 2013. He is white, 6ft 1ins tall, of slim build and has links to Doncaster, in particular the Wheatley Park area.
Police has advised members of the public not to approach him.
Young offenders will be ordered to go to bed early under strict new rules announced by the justice secretary.
Chris Grayling has announced that 15-17 year-olds in English institutions will have to be in their cells with lights out by 10.30pm.
"In some prisons young people are allowed to go to bed when they please. I don't think that is right. Stopping this inconsistency and introducing a strict 'lights out' policy is all part of our approach to addressing youth offending," the justice secretary said.
Teenagers who refuse to obey the new rules will be penalised and lose privileges such as access to a television.
More than 800 under-18s are serving custodial sentences in young offenders institutions.
Mr Grayling said: "It is also crucial that young people, most of whom have had chaotic and troubled lives finally get the discipline so badly needed to help turn their lives around.
An offer of sunscreen to inmates who climbed onto a jail's roof in hot weather was "foolish", the prisons minister has said.
Jeremy Wright said that he has ordered an immediate review into the matter.
"This should not have happened," Mr Wright said.
"There should be no policies in place which promote this kind of foolishness and I have ordered an immediate review of this incident to ensure that it does not happen again."
Two prisoners who climbed onto a jail's roof in hot weather were offered sun cream by staff "in line with health and safety rules."
The duo turned down their offer during the incident at Dartmoor prison earlier this month.
It is not clear how the inmates managed to get onto the roof or which building on the Devon site was involved.
The Ministry of Justice said the suntan lotion offer was due to health and safety rules.
A convicted killer jailed for life for raping a disabled woman has absconded from a mental health centre.
Police have launched a manhunt after Samuel Lee, 44, failed to return from an authorised trip from the John Howard Centre in Hackney on Thursday.
He is serving a life sentence for snatching and raping a 31-year-old cerebral palsy sufferer in London in 2000.
In 1989, he was jailed for manslaughter after he stabbed a man to death.
Police are warning the public not to approach Lee, who they warned could turn "violent".
Lee, who is black, of stocky build and 5ft 9ins tall, suffers from Schizotypal disorder which is a mild form of Schizophrenia.
Two prisoners who went missing from a prison in South Yorkshire have been arrested, police said.
Damien Burns and Dean Jackson absconded from category D Hatfield Prison on Tuesday.