He was just 21 when he carried out his first murder in 1974, and went on to kill three more people while he was in prison.
As a teenager, he funded his spiralling drug habit by working as a rent boy - his first victim being a client called John Farrell, who had shown Maudsley photographs of children he sexually abused.
Following the killing, Maudsley - now 67 - was jailed for life and sent to Broadmoor Hospital, where he killed a fellow inmate using a sharpened spoon - a brutality that earned him the nickname Hannibal the Cannibal.
Maudsley, from Toxteth in Liverpool, was then moved to maximum security Wakefield Prison in Yorkshire, where a further two murders took place in 1978.
It was at this point that staff at the prison decided Maudsley was too dangerous to remain among other prisoners and a special cell was constructed.
The two-cell unit, which was ready for Maudsley in 1983, measures just 5.5m by 4.5m and is contained within a series of bullet-proof windows.
It was subsequently dubbed the 'glass cage' due to its strong resemblance to the glass cage prison where fictional serial killer Hannibal Lecter was kept in the 1991 film Silence of the Lambs.
According to the Guardian, inside there's just a bed, table and chair, along with a toilet and sink that are bolted to the floor.
There's also a solid steel door that opens inside a small cage within the cell, with a small slot towards the bottom for guards to pass Maudsley food and other items.
The Guardian reported back in 2003 that Maudsley remains in the cell for 23 hours a day, and must be escorted to the yard by six prison officers for his hour of daily exercise, and he is not allowed any contact with the other inmates.
According to the newspaper, Maudsley - who became the longest-serving living British prisoner following the death of Ian Brady - wrote in 2003: "The prison authorities see me as a problem, and their solution has been to put me into solitary confinement and throw away the key, to bury me alive in a concrete coffin.
"It does not matter to them whether I am mad or bad. They do not know the answer and they do not care just so long as I am kept out of sight and out of mind.
"I am left to stagnate, vegetate and to regress; left to confront my solitary head-on with people who have eyes but don't see and who have ears but don't hear, who have mouths but don't speak. My life in solitary is one long period of unbroken depression."
In 2000 he filed an application to kill himself by taking a cyanide capsule, but it was denied after a five-day hearing. His request for a budgie was also denied.
Words by Jess Hardiman
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