Karen Butt, 26, had already abused staff at St Michael's Hospital and attempted to break a window to get hold of glass to kill herself when she told police of her intention to make a "firebomb" if released from custody, a court heard.

The voluntary patient at the Cape Road site told a police inspector: "I need to let you know that I intend to firebomb the hospital when I get out.

"I've done it before. I lost my temper one night and tried to blow up a pub in Oxford. There's no way you'll stop me until you remand me in custody."

She added: "I'm scared I'll end up killing someone, so prison's the only place left for me."

At an earlier hearing, prosecutor Vicki Lofrese told how Butt, of Birmingham Road, Stratford, had an argument with care workers at St Michael's in February.

She became abusive and violent, and picked up a fire extinguisher in an attempt to break a window.

Staff feared for their own safety as well as the defendant's, and restrained her until the police arrived.

During a visit from community psychiatric nurse Anthony James at Leamington police station, Butt said she would blow up the reception area at St Michael's, adding she would kill herself and hurt or kill other people.

She repeated the intention in formal interviews and later pleaded guilty to using threatening words and behaviour with intent to cause fear of violence and threatening to damage or destroy property.

At the resumed hearing, after reading the two psychiatric reports, Judge James Pyke observed: "Both of them say she meets all the pre-requisites for the making of a section 37 hospital order."

Without being addressed by defence barrister, Ian Speed, he added: "I will make that order now."

Butt will be detained in a secure psychiatric hospital until she is well enough to be released.