A prison officer has been taken to hospital with facial injuries after he was stabbed by an inmate, the Prison Service has confirmed.
The Prison Service also said a small fire had broken out amid the 'incident at height' at Swaleside Prison on the Isle of Sheppey in Kent.
There is an ongoing incident at height at HMP Swaleside. Two prisoners gained access to internal netting in an isolated incident. Specialist staff are at the scene waiting to bring the situation to a safe conclusion.
Two prisoners were involved, officials said, and one remains on netting on a prison ward after it was scaled by the inmates.
The problem of sexual violence behind bars is much more widely recognised in the US than the UK, campaigners have said, after an independent commission discovered the rate of sex crimes in prisons in England and Wales is broadly similar to the US. Frances Crook, chief executive of the Howard League for Penal Reform, said:
The focus and energy of both American Republicans and Democrats on tackling the issue of prison rape shames Westminster. The broadly comparable proportions of prisoners reporting sexual victimisation in the US and in England and Wales suggest that this issue is much more serious than previously thought.
Hundreds of prisoners may have been sexually abused behind bars, campaigners have said, prompting calls for more to be done to tackle prison rape.
An independent commission on sex in prison, set up by charity the Howard League for Penal Reform, discovered the rate of sex crimes in prisons in England and Wales is broadly similar to the United States.
Her Majesty's Inspectorate of Prisons (HMIP) data shows that 1% of prisoners report being sexually abused in prison, the Howard League said, meaning between 850 to 1,650 prisoners could be victims of sexual assault while inside.
The director of the Prison Reform Trust has called a south east London Young Offenders institution "grossly under-staffed, cash-strapped, overcrowded warehouse", after inspectors warned that there were signs of increasing violence at Isis due to its high population of gang members. Juliet Lyon said:
Time and again the Justice Secretary claims he is transforming rehabilitation, yet here is another example of a violent institution where far too many young prisoners spend the working day locked down with little or nothing to do save for half an hour of exercise.
The Governor and his staff have done some excellent work with the police to challenge gang affiliation in prisons, the chief executive of the National Offender Management Service said, after inspectors warned over high levels of violence. Michael Spurr added:
Isis manages a difficult population of young adult men - many of whom are serving sentences for violence and have links with London gangs.
As the Chief Inspector makes clear, Isis is an improving prison. In particular, it is doing really good work to support resettlement. Three quarters of prisoners go into employment or training on release - this is crucial for successful rehabilitation.
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.