A mentally ill Mitcham man, with a history of drugs and violence, could be facing life in jail for stabbing a university lecturer to death.

Mark Loveridge plunged a knife into Daniel Young's stomach, leaving him for dead, in a park near Morden Tube station on January 19 last year.

Loveridge will be sentenced today (October 27) at the Old Bailey where he could be facing either a discretionary life sentence or a hospital order.

Mr Young, 30, was due to start the second day of his "dream job" teaching tourism and hospitality at Coventry University London Campus.

Half an hour before, Loveridge, 39, also attacked 23-year-old Polish builder Kamil Bulat as he put tools into his car.

Loveridge stabbed him in the buttocks some 300 metres from the home he shared with his mother and stepfather in Mitcham.

In between the attacks, the part-time gardening assistant had phoned his boss to say he was going to be late.

On stabbing Mr Young in the stomach, Loveridge threw the 10cm blade into bushes and continued on his way to work as his victim bled to death in Kendor Gardens.

The same day, police recovered the knife from the park and tests revealed it had DNA on it belonging to both victims and their attacker.

Days later, Loveridge was detained following a struggle with police officers.

In custody, he told a psychiatrist he had been hearing voices and was carrying a knife out of "habit".

The defendant, who has paranoid schizophrenia, pleaded guilty to the manslaughter of Mr Young by diminished responsibility and to wounding Mr Bulat with intent to cause him grievous bodily harm.

Consultant forensic psychiatrist Philip Joseph told the court Loveridge had a history of drug abuse which made his condition worse and could trigger it.

His condition could be managed but, before the killing, Loveridge had stopped taking his medication routinely.

Dr Joseph told the court Loveridge believed he was under police surveillance and was being persecuted.

Members of Mr Young's family have travelled from their home in Torbay, Devon, to attend the sentencing by Judge Mark Lucraft QC.

Mother Julie Young said her son was "the rock" of the family and a "bright star".

He was "exciting" and "dynamic" as a businessman and sportsman and his "enthusiasm for life rubbed off on so many people", she said.

She said his father was now a "broken man", saying: "This type of grief knows no bounds. Our lives will never ever be normal again."

Mrs Young has been accompanied by her other sons, including 18-year-old Thomas who said the randomness of the killing made dealing with it "100 times worse".

He said: "It's destroyed the family. No-one is the same. This has just changed the whole dynamic of the family."