Duncan Heaton, 53, appeared at Leeds Crown Court and pleaded guilty to attempting to murder David Minto at HMP Wakefield.
Last month, Heaton also admitted trying to murder Andong Abong Ashu at HMP Full Sutton near York, a prison he had previously served time in.
There are currently fewer than 80 people in UK prisons serving a whole-life sentence, which is reserved for the gravest of crimes.
Heaton’s barrister, David Godfrey told the court his client wanted his sentence to be “as long as possible, a whole-life order”.
Mr Godfrey added: “He feels anxious about any other form of sentence.”
Heston was given a minimum term of 21 years and six months in 2014 for stabbing 51-year-old Keith Opray to death in the Bransholme area of Hull in 2014.
The court was told the defendant was currently held apart from other prisoners at Wakefield due to the risk he posed – and for months his only contact had been with prison staff.
He is due to be sentenced on 6 May.
Judge Bayliss said: “It’s going to be a life sentence.
The issue will be the term of that sentence.”
David Minto – lured Sasha Marsden to her death on the false promise of a job in his girlfriend’s hotel. The injuries inflicted on the teenager, from Staining, near Blackpool, were so severe that she had to be identified by DNA from her toothbrush.
Ashu was convicted in 2016 of:
• Four counts of rape
• Seven counts of sexual assault
• All committed against a young girl in Hull, East Yorkshire, beginning when she was just 11 years old.
21st April 2026
A convicted murderer has applied for a whole-life sentence after admitting to attempting to kill a fellow inmate at one of the UK’s most secure prisons.
