The mother of a woman with manic depression is to make an official complaint after her daughter was arrested and discharged from psychiatric care while she was in the grip of a psychotic episode.

Sandra Grant says she fears her 32-year-old daughter Alexandra may try to harm herself because staff at Bethlem Royal Hospital are refusing to treat her.

Alexandra, who suffers from bi-polar disorder, was admitted to the Beckenham hospital on July 10 after attempting suicide.

A week later she suffered a psychotic episode during which she set fire to her pillow.

Sandra says the small fire was put out and no one was injured but Alexandra smashed a window when she was threatened with sedation.

Once she was sedated Sandra says police arrived at the hospital and arrested her on suspicion of criminal damage but released her without charge hours later.

Sandra said: "Staff at Bethlem took the clinical decision that she was having a psychotic episode. If you knew someone was having a psychotic episode, why would you have them arrested?

"They didn't give the police any of her medical information. She had been given a sedative and the police didn't know she was sedated. What if she'd had an allergic reaction?

"The first I knew of it was when the police phoned me at 8am to ask me to collect her from the station. I learned that the hospital discharged her that same night."

By 11am that day Sandra was asked to collect her daughter's clothes from the hospital and had a meeting with her daughter's doctor, GMTV psychiatrist Raj Persaud, who is based at Bethlem.

Sandra added: "I am still unclear exactly why staff are refusing to treat her. I asked them if they thought it was right to arrest and discharge someone who was having a psychotic episode. All her doctor said was that he would investigate.

"Since she's been discharged Alexandra's tried to kill herself on two more occasions. She's under the care of the community but it's been 10 weeks and she hasn't even had a care assessment yet."

Alexandra has been living with her mother in Sutton Gardens, Woodside, since being discharged from Bethlem.

A spokesman for South London and Maudsley NHS Trust, responsible for Bethlem Royal Hospital, said: "We won't be able to comment on individual cases but we can say that the care, treatment and safety of our patients is of the highest priority.

"We have set up a patients advice and liaison service and there is also a complaints procedure which patients or their carers can go through."