A man who stabbed the mother of his child to death admitted to police that he would have carried on stabbing her if he had not hurt his hand, a court heard.

Marvin Samuels of Conduit Way, Stonebridge went on a vicious spree of attacks resulting in a lone dog walker being raped and beaten and the murder of his ex girlfriend, the Old Bailey heard.

On September 29 last year, the 31 year-old big-built, shaven-head man attacked a woman as she was walking her chihuahua around the Welsh Harp reservoir, he dragged her into the undergrowth before raping her and beating her with a branch then straggling her with her scarf.

She was found the next morning by her husband, confused and scared.

On the same evening, Samuels went onto knife his ex girlfriend, a mother of four, Sharlana Diedrick 16 times, telling police that he would have carried on if he had not hurt his hand.

Prosecuting Samuels was Duncan Atkinson, he said: "Neighbours reported that they heard screaming and a female shouting for help, they also said they saw a tall black man leaning over the car and a female body slumped in the seat. Moments after the stabbing Samuels sent his mother a text message with one kiss in it."

At 3.30am the next day, Samuels handed himself into Wembley police station.

Mr Atkinson spoke of the first incident saying: "She simply was in the wrong place at the wrong time. He attacked the woman while stressed about his relationship with Sharlana Diedrick. He said he knew what he was doing.

"Having left her for dead, only a few hours later the defendant stabbed Sharlana Diedrick as she sat in her car using a knife which he had armed himself with in advance."

Mr Atkinson went on to tell the jury that Samuels and Miss Diedrick had a 'volatile' relationship.

That evening Samuels had travelled from Harlesden train station to Watford station, he then got a lift back with Miss Diedrick to his mothers house in Conduit Way but they pulled up around the corner so that they would not be seen together due to social services being involved in their relationship and the custody of their son.

Samuels surrendered to police and told detectives he was responsible for the assault on Miss Diedrick, he told police: "I was different that day, I wasn't in my right mind. I was awful crazy."

Mr Atkinson added: "The defendant admitted he had lost it completely. He further admitted stabbing Miss Diedrick in the car during the argument. He would have stabbed her more had he not hurt his hand during the attack."

Samuels admitted raping the lone dog walker, and causing her grievous bodily harm, after forensics linked him to the assault, but he has denied her attempted murder and the murder of Sharlana Diedrick.

Mr Atkinson told the jury that they had to decide what Samuels’ mental state was at the time of both attacks.

The trial continues.