A MENTALLY ill man who stabbed his mother’s boyfriend to death on the front doorstep of their family home was jailed indefinitely.

Lee Byatt, 32, of Mildmayes, Laindon, was suffering from paranoid delusions when he attacked 46-year-old Colin Ricketts with a kitchen knife.

Byatt, who kept a stash of knives in his bedroom, claimed he was trying to protect his mother after seeing the couple arguing in the front garden.

Mr Ricketts pleaded with Byatt to call him an ambulance as he lay bleeding on the ground, Southwark Crown Court heard.

Byatt walked back into the family house to tell his mum to phone 999, only to return outside and plunge the knife into Mr Ricketts’ chest.

The dustman died in hospital less than 12 hours later.

Judge Anthony Leonard QC passed a sentence of imprisonment for public protection and ordered Byatt serve a minimum of five years before being considered for parole.

However, his sentence was indefinite, so he could be kept in prison for life.

The judge said: “You said the reason you stabbed Mr Ricketts was because you had seen your mother beaten up all her life and felt tension and rage.”

In the days before the stabbing Byatt became increasingly paranoid his mother and Ricketts were trying to poison him.

Byatt, who suffers from schizoid personality disorder and paranoid delusions, had been at home on the evening of April 26 last year chatting on the internet with friends.

His mother and Mr Ricketts returned from the Joker Pub in Laindon at around 1.30am and started rowing loudly in the front garden.

Byatt went to the door brandishing a kitchen knife and ordered his mum to come inside.

He slammed the door on Mr Ricketts and returned to his bedroom.

But just a few minutes later Mr Ricketts started banging on the front door and Byatt warned him through the letterbox that he would “put the knife in him” if he did not leave.

Byatt then opened the door and plunged the knife into his stomach.

He later told detectives: “He was outside egging me on, so I stabbed him. I only did this to protect my mum.”

Byatt was initially charged with murder, but entered a guilty plea to the lesser charge of manslaughter due to diminished responsibility during his trial at Chelmsford Crown Court in May.