Sarah Beynon, a 22-year-old insurance clerk, had been allowed out of a secure clinic in Bristol where she was being treated for schizophrenia when she carried out the killing with a hammer.
She pleaded guilty to manslaughter due to diminished responsibility at Bristol Crown Court in May last year. The court heard how she attacked her father Colin in the garden of the family home and battered him to death with a mallet and a hammer taken from his toolbox. She is now detained indefinitely in Broadmoor.
The inquiry, published yesterday, shows that the string of errors began soon after Miss Beynon was first admitted to the mental health unit of Southmead Hospital, Bristol, in August 1994.
The report describes how her medication was poorly monitored; she was not screened for drug abuse despite admitting to taking ecstasy; there was a lack of communication between social workers; and the risk she posed was not formally assessed.
She was given leave from Southmead despite her mental state and the report revealed that her unauthorised absences sometimes took place with her father's collusion.
Many risks were taken, without calculation". It said: "[Miss Benyon] behaved repeatedly in a way which created a risk of serious harm both to herself and others."
In January 1995, Miss Beynon was moved to the acute ward at Fromeside secure unit in Bristol where she was often the only woman among 15 men, despite staff being "well aware of the tensions and difficulties" this produced.
The report, whose chairman was Professor Bridgit Dimond, said: "Up until early June 1995, the clinical team were well aware of [Miss Benyon's] dangerousness, however, from July [she] largely controlled her contact with staff at Fromeside and other mental health workers."
The inquiry said the killing "could probably not have been avoided" although the risk "might have been reduced".
Ann Lloyd of the Healthcare Trust which runs Fromeside Clinic said: "It was a desperately tragic event and we would like to place on record our sincere regrets to Sarah's family. We acknowledge the shortcomings highlighted in this report."
In a statement, Jenny Beynon, Sarah's mother, said: "While I welcome Professor Dimond's report, I sincerely hope it will not be left to gather dust, but will be implemented quickly and effectively and that adequate resources are made available to do so."
- Glenda Cooper, Social Affairs Correspondent