Peter McGarry binged on cocaine and alcohol before fatally attacking his 76-year-old dad Malcolm McGarry at his home in Northfield Close, Sutton-in-Ashfield.
Police officers found Mr McGarry unconscious in the living room with severe head and facial injuries after being called to the address in the early hours of 1 December last year.
At a sentencing hearing yesterday (2 August), Nottingham Crown Court heard McGarry was under the influence of cocaine and alcohol and that he told officers he believed he had attacked a drug-dealing intruder, not his father.
McGarry, of Alexandra Street, Kirkby-in-Ashfield, pleaded guilty to murder in April and received a life sentence this afternoon, with a minimum custodial term of 14 years and 123 days – reflecting the time he has already spent in custody.