A woman who killed her two children and attempted to murder a third while suffering from depression has pleaded guilty to the crimes.

Coulsdon shop owner, Sasikala Navaneethan, 36, from Park Lane, Carshalton, stabbed her two children Shanjayan Navaneethan, five, and his four-year-old sister Sharani to death in October 2007.

The third child, Trishana, aged six months old, was taken to hospital suffering from serious injuries but made a full recovery.

During her incarceration, Navaneethan gave birth to a fourth child which is now in the care of her father Navarajah.

Both Mrs Navaneethan and her 39-year-old husband were arrested, but Mr Navaneethan, who also runs the newsagent in Coulsdon, was released without charge after questioning.

The couple, originally from Sri Lanka moved to Britain eight years ago and moved into their two-storey detached house in Park Lane two years ago.

A relation said the housewife had become depressed after her brother and his wife moved out of the four bedroom house.

Speaking through an interpreter, the relative, known as Sassy, told the Times: "Her husband was working all hours and she was very lonely with no one to talk to. She had three children that were very hard work."

At the time neighbours reported seeing the children, covered in blood, carried from the house late at night on May 30.

Shanjayan and Sharani died within 15 minutes of each other shortly after arriving at hospital.

Angie Silverstein, a local motor company worker near the couple's grocery shop in Coulsdon, said: "She was very unhappy, she always looked very sad.

"Now looking back, everyone said she was miserable, now I feel really sorry for her. She just looked sad and lost, and she obviously was.

"It's a shame that somebody, a GP or someone didn't diagnose anything. What has shocked everyone is that it got to this point."

Navaneethan has been sentenced to indefinite detention at a mental hospital.