A double murderer died under guard in a hospice after a 12-month battle with oesophageal cancer, a coroner said.
Royston Jackson, 52, was serving a whole life term in HMP Whitemoor, and died in Thorpe Hall hospice in Peterborough in March.
He was told his condition was terminal in December 2018 after the cancer spread to his liver and lungs.
Cambridgeshire assistant coroner, Simon Milburn, concluded Jackson died of "natural causes".
During a five-minute inquest at Peterborough Magistrates' Court, Mr Milburn said two prison guards remained at Jackson's side at all times until his death on 10 March.
According to the Ministry of Justice, Jackson was among 63 prisoners in England and Wales serving a whole life order - where offenders are jailed for life without the possibility of parole or conditional release.
'Very dangerous man'
Jackson, a turkey catcher from Norwich, was convicted of the murder of Gordon Boon, whose body was found dumped in a lane at Great Witchingham, Norfolk in 2008.
The killing took place two years after Jackson had been released after serving 16 years of a life sentence for the murder of teenager Stephen Raven in Essex in 1989.
The judge at his trial described him as a a "very dangerous man".
He was an inmate at HMP Whitemoor in Cambridgeshire, a Category A prison holding 500 of the most dangerous criminals in the UK.
Mr Milburn said Jackson had been diagnosed with oesophageal cancer in March 2018 and began chemotherapy treatment four months later.
The cancer had spread to his liver, lungs and abdomen by December 2018 and he was placed in palliative care.
He was admitted to Thorpe Hall three days before his death.
"Sadly that disease progressed to its natural conclusion," Mr Milburn said.