THE Sun has gone on a rare tour of a notorious UK prison recently branded "inhumane" - but it wasn't what you would expect.
A cutting-edge "jail of the future" has been built against the odds inside HMP Pentonville in north London.
The lock-up's pioneering "neurodiversity wing" has been lauded by experts who say it offers hope for solving Britain's prison crisis.
This week our reporter went inside the wing - and it could not have been more different from "The Ville's" tough reputation.
Last year inspectors branded category-B Pentonville "neither decent nor humane" for prisoners to live in.
Many prisoners share a 12ft by 8ft cells with a cellmate - living and eating just inches from an open toilet.
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The Victorian prison was found to be crumbling and infested with cockroaches and vermin.
Inspectors told how "drain blockages caused sewage to erupt through a manhole".
The overflowing caused "extremely unpleasant conditions in the care and separation unit and an adjacent newly refurbished wing".
On other occasions burst pipes have leaked through the roof and prisoners have gone without heating, electricity or running water.
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Pentonville is designed to hold 500 men but currently has about 1,200.
Shockingly, only a hundred or so of its inmates have been found guilty of a criminal offence.
The rest are on remand, imprisoned for up to 14 months before standing trial - where a large number end up acquitted.
It is hard to think of an environment less promising as a place for troubled young men to turn their lives around.
But Pentonville's staff have worked against the odds to create a more hopeful environment - including the new neurodiversity wing.
Pentonville is split between arrival cells, the general prisoners wing, the drug and alcohol addiction wing and the gangs wing.
The gangs wing is in turn split up to keep apart rivals from the Tottenham and Hackney postcode wars.
When hostile inmates cross paths, disaster can follow - like when 21-year-old Jamal Mahmoud was stabbed to death in G wing in 2017.
But the ground floor of G wing has now been taken over by the pioneering neurodiversity unit - which The Sun visited this week.
Most prisoners currently behind bars in the UK have mental health issues, learning disabilities or neuro-diverse needs like autism, OCD or ADHD.
Many also suffer from heartbreaking childhood trauma - which is even more difficult to process because of their special needs.
A Pentonville source told how many inmates in the prison were introduced to crack, heroin or alcohol as babies or toddlers.
Others grew up witnessing or suffering horrific domestic abuse, including sexual abuse.
And many have spent their lives in extreme poverty or the notorious pipeline from institutional children's care homes to prison.
Youngsters growing up with these ordeals often stop going to school by their early teens or get excluded after lashing out.
The result is that many end up dogged with mental health troubles or substance addiction, while lacking even basic literacy or numeracy.
INSIDE 'THE VILLE'
Any of us would struggle if we were dealt such a hand - but it is even harder for a person with neuro-diverse needs.
Overseen by Custodial Manager Neil Fraser, the NDU wing hosts 43 inmates with severe learning disabilities or mental health issues.
When The Sun visited the wing, they were on association - the hour where prisoners can leave their cells to mingle.
Our reporter went inside the wing's sensory room, a converted cell kitted out with beanbags and soothing multi-colour displays.
Prisoners who are panicking, depressed or angry can come here for around twenty minutes by themselves to calm down or even nap.
A prison officer who has served on the wing told how violent trouble-makers in the general wings have become far more gentle in NDU.
They told The Sun: "We get to know all of them as individuals, beyond just their names and offences.
"I know if a certain prisoner is particular about how his spaghetti is cooked or whether it should be in a plate or bowl.
"Or whether they are calmer with their cell door open or shut, and when.
"It massively improves their mood and makes them much less of a danger to others or to themselves.
"On the general wing there are hundreds of prisoners, many of whom have similar needs.
"I'm lucky if I know their name, what they're in for and when their last visit was.
"The NDU wing is a model of how all prisons should be run in this country."
Prisoners in the wing are given the freedom to express themselves with safe materials.
One burly lag showed The Sun a dozen or so model planes, trains and cars he has made from mulched-up crisp packets and milk cartons.
Another has lined his room with his drawings of animals and landscapes, as well as a Chelsea pennant.
Officers were seen chatting and even patting inmates in a display of warmth unimaginable in some UK prisons.
WINGS OF HOPE?
Pentonville has launched a string of other schemes in a bid to make rehabilitation possible in its cramped and crumbling wings.
Custodial Manager Ricardo Lafuente-Dyer runs a workshop called Time4Change, where prisoners can discuss their experiences openly.
The workshop explores why crime is such a powerful draw for troubled youngsters.
Prisoners also talk about problems like poverty, domestic abuse and racism - and how to be part of a society which they feel hates them.
One former Pentonville inmate told how he entered the prison in a dire mental state after his best friend was murdered.
He was jailed shortly before the birth of his daughter - and only saw her three times in 18 months because of lockdown restrictions.
But following his release he now works as a prison healthcare adviser for the NHS - saying the workshop helped him change his life.
Former prisoner Dan Brown told The Sun how Pentonville's chaplain Jonathan Aitken helped him get on the straight and narrow.
Dan spent the better part of a decade in Pentonville for a range of offences relating to substance addictions.
He was eventually released, only to smash up a pub while raiding it for alcohol.
But former cabinet minister and Belmarsh inmate Aitken did not give up on Dan, who is now a tradesman, husband and new dad.
The Sun's reporter attended Dan's wedding last year, which Aitken officiated.
Pentonville also teaches inmates skills like carpentry or industrial and biohazard cleaning before setting them up with friendly employers.
On Monday Chief Inspector of Prisons Charlie Taylor opened a new XO Bikes training workshop at Pentonville.
At the ceremony, Taylor gave three inmates certificates marking their progress as trainee bike mechanics.
And from September former Speaker John Bercow will teach a public speaking course at the prison.
JAIL OF THE FUTURE
But the reality is that Pentonville is an old, cramped and crowded prison where most inmates are not rehabilitated.
The prison is also badly strapped for cash, with the NDU wing funded by a club of charities rather than the state.
A majority of prisoners would benefit hugely from living on the NDU wing - but there is only space for 43 out of more than a thousand.
Likewise, the prison is rife with addictive substances outside the one designated drug-free wing.
Many prisoners appear to go clean inside only to relapse after their release - quickly returning to prison, be it Pentonville or elsewhere.
One officer on the drugs wing told The Sun of the heartache of not knowing what has become of former inmates in his care.
He has built a rapport with many prisoners - but is barred from contacting them on release and knows how bad re-offending stats are.
Gangs target the concentrated market of addicts inside, allegedly using their members inside to smuggle in contraband.
Perhaps the most difficult prisoners to rehabilitate are those on G wing, whose inmates look down through the netting above NDU.
In recent years the Hackney-Tottenham cocaine war has mutated into a constantly shifting maelstrom of more than 50 postcode gangs.
G wing is a microcosm of the streets, with new arrivals freely owning up to their gang affiliations to avoid harm.
The mood of the wing is said to be paranoid, tense, lonely and prone to eruptions of violence - no place for rehabilitation.
Gang members sometimes face reprisals if they engage with officers, and a loss of face if they accept help for neuro-diverse needs.
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But a prison officer said at least one former G wing inmate has found a measure of peace after moving to NDU.
Pentonville has long been notorious as one of Britain's toughest prisons - perhaps it could soon stand out as the jail of the future.