The child killer was jailed for 45 years after being given a life sentence for the 1967 rape and murder of Walsall schoolgirl Christine Darby who was aged just seven.
The sadistic killer was also the prime suspect in the killings of Diane Tift, aged five, of Bloxwich, and Margaret Reynolds, six, of Aston, who vanished in 1965.
All three bodies were found dumped within miles of each other beside the A34 on Cannock Chase in 1966 and 1967. Each had been sexually assaulted and strangled. The killings horrified the nation and sparked one of the biggest murder investigations in British criminal history.
The police manhunt was larger than that of the infamous Moors murders by Ian Brady and Myra Hindley.
The Ministry of Justice today confirmed that Morris, from Green Lane, Walsall, died at the HMP Preston health facility on Tuesday at around 8pm. The former engineer had been transferred from nearby HMP Wymott where he had been serving his sentence.
It is believed he died of natural causes and the Independent Prisons and Probation Ombudsman has launched an investigation as is required by law.
The hunt for the Cannock Chase child killer saw 150 detectives visit 39,000 homes, interview 80,000 people and check more than a million car records before Morris's arrest. Morris was spoken to four times but slipped through the net when his wife gave him an alibi. She later became a key prosecution witness.
The twice married father-of-two was also linked to an attack in 1964 on nine-year old Julia Taylor who was lured into a car in Bloxwich by a man claiming to be a friend of her mother. She was strangled and left for dead but was saved when she was spotted by a passing cyclist.
Morris was sentenced to life in prison in 1969 after a trial at Staffordshire Assizes in Stafford found him guilty of the murder and rape of Christine Darby. He had denied the charges.
In recent years he had made a bid for release still claiming his innocence. Solicitors began challenging his sentence through the courts, claiming to have uncovered police misconduct. But the case was rejected by the Criminal Cases Review Commission in 2010.
Last month it was confirmed that Morris would die in jail after the Court of Appeal found whole-life sentences should continue for the most heinous crimes - that life would mean life.
Christine, Margaret and Diane lived within a 17-mile radius of each other and were found near the A34 Cannock to Stafford road that passes through Cannock Chase.
The cases of Margaret and Diane were left unsolved but kept on Morris's file.
Morris, who was denied parole in 1999, was one of Britain's oldest serving prisoners. He was said to have lived a solitary and largely anonymous existence in HMP Wymott. A Prison
Service spokeswoman today confirmed Morris had passed away. She said: "HMP Preston prisoner Raymond Morris died at around 8pm on Tuesday March 11, 2014 of suspected natural causes.
"As with all deaths in custody, the Independent Prisons and Probation Ombudsman will conduct an investigation."