Serious questions have been raised about the mental health treatment of a mother who laid down before a speeding train cradling her toddler son, killing them both.

Donna Oettinger, 41, was denied urgent psychiatric help despite attempting suicide over "crippling" anxiety three months before she died at Riddlesdown station with three-year-old Zaki in her arms, an inquest heard today.

They were killed instantly when they were struck by a morning commuter train just yards from their home on March 22, 2013, 

On the inquest's emotional opening day, Croydon Coroner's Court heard Miss Oettinger, of Lower Barn Road, had been plagued by fears cocaine had damaged her brain. She was also left devastated when she discovered Zaki's father, her partner of seven years, had a secret wife and child in Egypt.

In the 10 months before her death, she twice held a knife to her own neck, had to be physically restrained from throwing herself under a train at East Croydon, and overdosed on prescription anti-depressants.

After the overdose in December 2012, a community mental health worker recommended Miss Oettinger received "intensive home therapy", which would see her receive two or three visits from doctors or nurses each day.

But Dr Hemanth Rao, a psychiatrist at South London and Maudsley NHS Trust, assessed her as being low suicide risk and instead placed her on a nine-month waiting list for therapy.

Carol Oettinger, Donna's mother, told the inquest: "Donna said she was unhappy to have survived her overdose attempt. We told Dr Rao about the home treatment recommendation but he said he could not help."

In tearful evidence to the court, Miss Oettinger's mother recalled her daughter's rapid deterioration from "a confident, caring person" to being so wracked by anxiety and panic attacks she had to give up her job as an accountants assistant and could barely look after Zaki.

She said: "She was constantly talking about anxiety. She would follow you around and you would have to sit down and talk to her about her anxiety.

"She said to me, 'I can't live with it mum. You are going to lose me."

Dr Rao told the court that after meeting Miss Oettinger days after her overdose, he considered her a low suicide risk. He also said he did not think Zaki was at any risk of harm.

He said: "This was a person who was not living alone and who had an awareness of their illnesss. 

"She presented as someone who doted on her child and loved him very much."

The court heard a harrowing account the final moments of Miss Oettinger and her son from the driver of the train that killed them.

In written statement, driver Patrick Cusack said: "She had an arm, a protective arm, an almost consoling arm around the child.

"I thought, 'oh god I hope I don't hit him' because I knew I was going to hit her."

The inquest is expected to conclude on Wednesday.