A woman care worker was stabbed to death by a resident at a care home where he should never have been sent, a jury were told today (Wednesday).

Abacus House in Dunstable was unsuitable for the care and treatment of the male patient, who suffered from bipolar disorder, it was alleged.

Staff at the home were more used to dealing with "acquired brain injury," such as people who had been involved in road accidents or patients who had suffered a stroke or who had problems due to alcohol or drug use.

The patient sent there, Stephen Flatt from St Albans, could be aggressive and violent and in the past had carried offensive weapons, Luton crown court was told.

He had been known to exhibit sexually inappropriate behaviour to women.

However, in the summer of 2007 he arrived at Abacus House, placed there by the Hertfordshire Partnership NHS Foundation Trust.

The trust is on trial accused of breaching health and safety rules when it placed him there.

It's claimed by the prosecution that the home was "completely unsuitable" for Flatt.

Not only that, but it's alleged that it failed to carry out a proper risk assessment before placing Flatt there and, at the time, was an unknown quantity because until then the trust hadn't had any dealings with Abacus House.

The trust pleads not guilty to contravening a health a safety regulation by failing a suitable and sufficient assessment of the risk Flatt posed.

It also denies a second charge of failing to discharge a duty to ensure persons not in its employment were exposed to risks to their health and safety.

The owner of the home Chelvanayagam Menna, 58, of Periwinkle Lane, Dunstable, pleads not guilty to three charges under the Health and Safety act that he failed carry out a proper assessment as to the risks staff and other patients were exposed to by the arrival of Flatt.

Mr Flatt arrived at Abacus House on July 18 and the following month stabbed care worker Kathleen Bainbridge, 58, to death and attacked another woman member of staff, Barbara Hill.

Today Rex Tedder QC prosecuting, said that Abacus House was not "geared up" to be able to cope with Mr Flatt, who suffered from a bipolar disorder The court was told Mr Flatt, who lived in the St Albans area, had a long history of mental problems going back to the late 1970's.

He had been diagnosed as suffering from paranoid schizophrenia. In the past he had been violent and was convicted of assaulting his father and a policeman. He carried offensive weapons and there were periods when he was judged to be a danger to himself and others.

Later he was diagnosed as suffering from bipolar disorder.

On New Year's Day 2007 Flatt, who was 55, was sectioned under the Mental Health Act and admitted to Albany Lodge in St Albans, a psychiatric unit run by the trust.

He remained in an intensive care unit for two months and later that spring spent a number of weeks in another psychiatric unit in St Albans before returning to Albany Lodge.

The jury heard it was around this time that both his elderly parents died.

Mr Tedder told the court: "A further placement was in the offing. The prosecution's case is that the further placement that was selected was highly unsuitable."

He also said that sending Flatt to Abacus House following the deaths of his parents meant "the timing was wrong" which he said had serious consequences.

Mr Tedder said staff at the residential care home were not trained to deal with patients suffering from bipolar or how to manage it.

Instead Abacus House was more used to treating people with "acquired brain injury" he said, such as road accident victims or patients who had suffered a stroke or who had problems due to alcohol or drug use.

The jury were told that Hertfordshire Partnership NHS Foundation Trust had never sent anyone to Abacus House before Mr Flatt.

As a result said the prosecutor it was "an unknown quantity."

He said "The reality is that Abacus House was a completely unsuitable placement for him. Staff had no understanding of the risk he posed."

The prosecution say enquiries the trust made with Abacus House before sending Mr Flatt there were "simply inadequate."

Mr Tedder said "The trust had a duty to ensure that staff and residents at the new placement were not put at risk. The prosecution say the trust failed in that duty."

He said "Abacus House was not geared up to be able to cope with Mr Flatt, who was bipolar. The ladies employed there were not nurses and not trained in the management of the bipolar condition. The reality is that Abacus House was a completely unsuitable place for him and staff had no understanding of the risk he posed.

"The enquiries the trust made before he went there were simply inadequate."

Mr Tedder said the normal procedures for introducing someone to a new home or unit would entail a day visit with a carer followed by a longer spell so a patient would get used to it gradually.

This didn't happen in Flatt's case.

The jury were told that since 2005 when a resident of Abacus House had died, no replacement had been found which meant a loss of income of £1000 a week or £50,000 a year.

As a result, said the prosecutor, there were cashflow problems for Abacus House and Mr Menna had been "determined" to take Flatt without fully considering the risks he posed.

He went on "Mr Menna should have made a risk assessment and made sure staff were not put at risk and the prosecution's case is that he failed in his duties.

On August 24, just weeks after arriving at Abacus House, Flatt stabbed Mrs Bainbridge to death while she was at work there and seriously injured a second care worker.

The case continues