Prison staff 'feared for their lives' and retreated to safety when between 160 and 180 inmates began smashing up the Thanet wing this afternoon.
It is unclear what prompted the riot, but it came one day after Justice Secretary Chris Grayling banned violent and sexually explicit films as part of a clampdown on perks.
National resources were deployed to cope with the violent outbreak, which involved up to 200 inmates in the Category C jail.
Officers carrying riot shields leave Maidstone Prison in Kent after the three-hour violence was eventually quelled
The riot was eventually quelled after special officers were drafted in to negotiate peace
A police officer stands at the road to Maidstone Prison in Kent as emergency services shut off the roads surrounding the huge jail
Inmates had come to expect a certain regime at the low category prison, but drastic cuts to the prison service meant they were having to spend more time locked in their rooms
The inmates attempted to destroy the wing by smashing it up, and some prison staff retreated to safety, according to the Prison Officer's Association (POA).
National resources were drafted in, which is believed to be the prison service's Tornado Team of officers specially trained in dealing with riots.
Ambulance services were called after the row began to get out of control at around 4pm.
HMP Maidstone holds inmates including sex offenders and foreign nationals with more than 18 months left to serve.
The POA's Vice Chair, Ralph Valerio, said negotiators managed the scene as the rioters smashed and destroyed the wing.
He added that some staff may have been assaulted in the attack but retreated to safety.
The rioters' demands were believed to be largely based on how prisoners were spending more time in their cells
The POA praised the professionalism of prison staff and said they would be well trained in how to negotiate with the inmates
Emergency services were called after officers managed to quell the disturbance, which lasted for hours
Mr Valerio said that prisoners began rioting following changes in the prison regime which meant they have to spend more time in their cells.
He told Sky News that inmates had come to expect a certain regime at the low category prison, but drastic cuts to the prison service meant they were having to spend more time locked in their rooms.
The trade union official said: 'The intelligence we are getting is that the demands are largely based on on the 'curtailment of regime' - the curtailment of regime means more time spent behind the door.
'Try to put yourself in the shoes of the offender - you find yourself spending more time locked up with less time to be able to call your family and less time to be able to have social interaction with the staff and with other offenders on that wing then it can have a detrimental effect.
'As a trade union we have been warning against this for some time. The prison system is going through a tremendous amount of change at a tremendous rate of pace and it's a warning that the rates of change is unprecedented.
Maidstone, with an inmate population of about 600, is a category C training prison that predominantly houses sex offenders from the Kent and Sussex areas
Operation Tornado - a special force of officers trained in negotiating - were deployed to cope with the 180 inmates in the Category C jail
Maidstone, with an inmate population of about 600, is a category C training prison that predominantly houses sex offenders from the Kent and Sussex areas
'The offenders who live at Maidstone come to expect a certain form of regime because they are considered to be of lower risk so they can probably get a better regime than perhaps elsewhere.
'But unfortunately from what we are hearing at Maidstone is that they are chronically short staffed and the result of that shortage of staff is the regime cut.'
He said what the staff are able to deliver has been 'drastically cut drastically quickly and we have been warning about that for some time'.
Eyewitness Jackie Hipwell, who lives near to the prison, said that she had been hearing shouts from around 4pm.
She said: 'Early on we could hear shouts and dogs barking,' she told Sky News.
'This has been going on since about 4pm, that's when we noticed it.
'My daughter couldn't go out as police cordoned off the road, and people can't get back in.'
Maidstone Prison is one of the oldest penal institutions in the United Kingdom, having been in operation for almost 200 years
Officers at Maidstone Prison 'feared for their lives' and were forced to retreat amid the outbreak
The prisoners began smashing up the wing in a riot that last for around three hours, before negotiators resolved the row
OPERATION TORNADO: HOW TRAINED OFFICERS CONTROL RIOTS
Steve Gillan, General Secretary of the Prison Officers Association said: 'We were made aware of concerted indiscipline at Maidstone Prison which is now being managed through the process involving Tornado officers.
'These are national tactical officers who have been given appropriate riot training and will be based centrally, in London, or at nearby prisons.
'Because these officers are involved, this does not necessarily mean there is a riot at the prison.
'It is routine for these teams to be called in if there is the threat of disquiet, so it may be that we're seeing something which is bubbling up here.
'The POA has been aware of a situation at the prison since around midday, but we're yet to receive a clear update so we cannot speculate on the seriousness of the problem.
'We have been warning of the dangers of declining numbers of prison staff since the government began to cut prison service budgets.
'It is a fact that we are now 2,000 prison officers lighter than we were when the coalition began its programme of cuts.
'A lack of staff in prisons will be a major contributory factor to situations like we're seeing at Maidstone now.'
'These are national tactical officers who have been given appropriate riot training and will be based centrally, in London, or at nearby prisons.
'Because these officers are involved, this does not necessarily mean there is a riot at the prison.
'It is routine for these teams to be called in if there is the threat of disquiet, so it may be that we're seeing something which is bubbling up here.
'The POA has been aware of a situation at the prison since around midday, but we're yet to receive a clear update so we cannot speculate on the seriousness of the problem.
'We have been warning of the dangers of declining numbers of prison staff since the government began to cut prison service budgets.
'It is a fact that we are now 2,000 prison officers lighter than we were when the coalition began its programme of cuts.
'A lack of staff in prisons will be a major contributory factor to situations like we're seeing at Maidstone now.'
Speaking to Sky News during the riot he said: 'What the prison service can't do is try to intervene unless it's got sufficient staff and resources to quell the riot.
'Given enough time and staff it's well trained to deal with these incidents.
'I'm confident that the prison service will regain control, but it's clearly a matter of time.
'It takes time to get enough staff with enough equipment and resources, then get a plan together to take the wing back.
'For the next two or three hours it's a concerning time for the service and the local community.'
Criminologist Professor David Wilson said prison guards used Operation Tornado to bring the latest riot under control.
It is a proven method using specialist officers that has been used many times before, he said.
'These are very well-tested systems and so it will be about trying to bring order back to HMP Maidstone,' he told Sky News.
'In these situations it's usually a question of being some particular incident that ignites the prisoners who want to take this kind of action and sometimes that action gets out of control.'
A spokesperson for the South East Coast Ambulance Service said: 'We were made aware of an 'incident' at 4pm and dispatched two vehicles from the hazardous area response team immediately.
'They are specially trained paramedics who will normally be called upon for situations like terrorist attacks, big fires and other unusual emergencies.
'They have been and are still on site in a supportive capacity.
'As yet they have not been required to treat anyone, but they remain at the prison in case they are needed.'
Category C prisons are for those who cannot be trusted in open conditions but who are considered unlikely to try to escape.
The rioting at Maidstone prison 'was a planned attack in an attempt to take control of the wing'
The POA vice chair said that prisoners began rioting following changes in the prison regime which meant they have to spend more time in their cells
HMP Maidstone holds inmates including sex offenders and foreign nationals with more than 18 months left to serve
Since 2009, it has accommodated around 400 sex offenders with around 200 foreign nationals not convicted of sex crimes in a separate wing.
It is mostly a category C prison, but does house some B category inmates.
East End gangster Reggie Kray married Roberta Jones at the institution on July 14, 1997.
Its website says it aims to 'create a therapeutic environment that supports, embraces and empowers change with a primary focus on risk reduction and protection'.
The prison also takes in a small number of foreign prisoners with more than 18 months to serve and provides forums with the UK Border Agency.
Kent Police confirmed they were aware of the incident, but a spokeswoman said prison services were dealing with the matter.
Ford Open Prison in West Sussexwas set on fire after about 40 inmates began smashing windows and eight blocks at the open jail were set on fire
Hours after the row, up to prisoners began rioting in a G4S-run Rye Hill, a private Category B prison, in Warwickshire, Sky News reported.
An MoJ spokesman said: 'There was a passive demonstration at HMP Rye Hill today where around 60 offenders refused to return to their cells. This was peacefully resolved within a few hours.'
The privately-run prison, which houses 664 inmates, seeks to 'normalise prison conditions as far as possible and reflect life in the outside community', according to the G4S website.
The incidentw follow a riot at Ford Open Prison, West Sussex, on New Year's Day in 2011.
It erupted after prisoners were ordered to undergo breathalyser tests for contraband alcohol.
About 40 inmates began smashing windows and activating fire alarms. The incident escalated and eight blocks at the open jail were set on fire.
Prison staff retreated from part of the site and specialist officers in riot gear were brought in.
Rioting prisoners also caused £1 million of damage during a five-day riot at Moorland Prison in Doncaster in 2010.
It began in the young offenders' wing when three staff members were assaulted and a female officer suffered a fractured jaw.
The longest riot in British history occurred over 25 days at Strangeways Prison in Manchester in 1990.
It began when prisoners took control of the prison chapel and trouble quickly spread.
One prisoner was killed and 147 prison officers and 47 inmates were injured. Prison repairs cost £55 million.
The riot sparked a series of disturbances in prisons across England, Scotland and Wales.
THE END OF EXPLICIT FILMS: HOW PRISONERS' PERKS HAVE BEEN CUT
Prisoners' perks have been slashed under new rules.
Explicit 18-rated movies, such as Hostel and Reservoir Dogs, will no longer be screened at jails in England and Wales under changes to the Incentives and Earned Privileges (IEP) scheme.
Inmates will also be required to wear a uniform for their first two weeks behind bars, and will lose automatic access to daytime television and gym equipment.
The IEP scheme allows prisoners to work up specific levels of privileges through good behaviour and, in turn, lose the perks if they fail to meet acceptable standards.
Last month, the Ministry of Justice also announced changes that will see prisoners pay compensation for damage caused.
Justice Secretary Chris Grayling said: 'For too long the public has seen prisoners spending their days languishing in their cells watching TV, using illegal mobile phones to taunt their victims on Facebook or boasting about their supposedly easy life in prisons.
'This is not right and it cannot continue.
'The changes we have made to the incentive scheme are not just about taking TVs away from prisoners, they are about making them work towards their rehabilitation.'
A full review of the policy - the first for 10 years - was ordered by minsters last year and was completed in April.
Explicit 18-rated movies, such as Hostel and Reservoir Dogs, will no longer be screened at jails in England and Wales under changes to the Incentives and Earned Privileges (IEP) scheme.
Inmates will also be required to wear a uniform for their first two weeks behind bars, and will lose automatic access to daytime television and gym equipment.
The IEP scheme allows prisoners to work up specific levels of privileges through good behaviour and, in turn, lose the perks if they fail to meet acceptable standards.
Last month, the Ministry of Justice also announced changes that will see prisoners pay compensation for damage caused.
Justice Secretary Chris Grayling said: 'For too long the public has seen prisoners spending their days languishing in their cells watching TV, using illegal mobile phones to taunt their victims on Facebook or boasting about their supposedly easy life in prisons.
'This is not right and it cannot continue.
'The changes we have made to the incentive scheme are not just about taking TVs away from prisoners, they are about making them work towards their rehabilitation.'
A full review of the policy - the first for 10 years - was ordered by minsters last year and was completed in April.
