MENTAL health patient Nicola Edgington was told "do us all a favour and cut your wrists" by her brother just days before two Bexleyheath knife attacks which she is on trial for.

Tom Edgington had contact with his sister for the first time since she was convicted in 2006 of the manslaughter of their mother Marion, a jury at the Old Bailey heard today.

In the Facebook exchange on September 28, 2011, mother-of-two Edgington reached out to her brother less than two weeks before she stabbed a grandmother she had never met before to death in the street, the court was told.

The message in 'text speak', in which Edgington claimed to have just had a miscarriage, was read to the jury of seven men and five women by prosecutor Mark Heywood QC.

It read: "sorry if u don't want 2 talk 2 mi im missin mum bad.

"to be honest no1s taking care of mi like she could an i don't think she would want us to be apart like dis."

The 32-year-old finished by posting her phone number, saying she loved her brother "always" and asking him not to tell their father Harry she had been in touch, the jury heard.

Tom Edgington responded: "you stabbed her to death and left me to find her body.

"good news about your miscarage tho, people like you should be steralised for the good of the world.

"do us all a faver and just slit your wrists."

Opening defence witness Dr Adrian Cree, a forensic psychiatrist, told the court of a "bizarre" claim made by Edgington when he assessed her in prison in 2005 while on remand for her mother's killing.

He said the defendant believed her boyfriend of two years was in fact the father of her first child who had come back to the UK in disguise.

Dr Cree said: "He had, in her belief, changed his appearance with plastic surgery, returned to Britain and started a relationship with her as 'Phillip'."

Dr Cree told the jury he was convinced Edgington is a paranoid schizophrenic based on his first meeting with her and a further assessment last year following the events of October 10, 2011.

On that day she is accused of attempting to murder Kerry Clark, 22, and murdering 58-year-old Sally Hodkin in two frenzied knife attacks in Bexleyheath town centre.

Unemployed Edgington, of Ambedkar House, Flavell Mews, Greenwich, denies one charge of murder and another of attempted murder.

She admits the stabbings but is pleading diminished responsibility on account of her mental condition.

The trial continues.