He is thought to have taken his own life.
Park was convicted of the murder of his wife Carol in 2005, nearly 30 years after he killed her and dumped her body in Coniston Water in the Lake District.
He was found hanging in his cell at HMP Garth, Leyland, Lancashire, this morning. Today was his 66th birthday.
Advertisement
Hide AdAdvertisement
Hide AdA Prison Service spokesman said: "HMP Garth prisoner Gordon Park was found unconscious in his cell at 8am on Monday January 25.
"Staff and paramedics attended but Mr Park was pronounced dead at 9.40am.
"As with all deaths in custody, the Prisons and Probation Ombudsman will conduct an investigation."