A man stabbed his 86-year-old mother with an ornamental sword then decapitated her and put her head in the freezer, a court has heard.
Philip Tarver, 47, allegedly attacked Angela Tarver and threatened his 83-year-old father Colin at the family home in Woking, Surrey, on December 19 last year.
Opening his murder trial at the Old Bailey, Alexandra Healy QC said: "It is the prosecution case that at around midday that day, in the kitchen of the address, the defendant stabbed his mother in the chest with an ornamental sword, killing her.
"Brandishing that sword in the dining room of the property he argued with and threatened to kill his father."
During a struggle, his father managed to disarm the defendant, before leaving to alert police, jurors heard.
Ms Healy said: "It appears that, whilst the police were making their way to the address, the defendant decapitated his mother, placing her head into the freezer in the kitchen.
"And he amputated her left ring finger, which he placed into a kettle."
Tarver began to clean up, washing himself and the knife he used to decapitate his mother, it was claimed.
When police arrived, he came to the front door "waving a Union Jack and saying he surrendered", Ms Healy said.
Following his arrest, Tarver heard his father was being spoken to by police and allegedly commented: "Oh of course his wife.
"His wife is in the freezer."
On arrival at the police station he said he was "sorry for killing her" adding that he "must repent my sins", the court heard.
During a mental health assessment, Tarver went on to explain how he killed his mother, jurors were told.
He was taken to a mental health hospital where he remained until March when he was deemed fit to be interviewed by police.
Tarver denies murdering his mother and making a threat to kill his father.