Edward Boylan, of no fixed abode, admits stabbing Edward Boylan Senior but claims he was having a full psychotic episode when it happened.

On Day 1 of this murder trial, the accused admitted stabbing his father with a WW1 sword before setting his flat in Kimmage on fire in Jan 2012.

Fire fighters found the 74-year-old with half of the 20 inch blade still embedded in his chest.

Just days after he was charged with murder, Edward Junior was admitted to the Central Mental Hospital where he was examined by two medical experts.

He told them a female voice in his head told him his father had raped her and asked him to do something about it.

The 31-year-old said he often suffered from hallucinations and believed people were planting thoughts in his head through the radio and TV.

Both experts concluded that he was suffering from a mental disorder at the time of the attack and both legal teams have asked the jurors to return a verdict of not guilty by reason of insanity.

They're due to be begin deliberations this afternoon.