A teenager armed with a knife waved his arms like an “orangutan” as he attacked a woman walking home through St Albans late at night.

Shane Simmonds, 18, pushed his victim to the ground and repeatedly stabbed her in a case of mistaken identity, last October a jury was told. The teenager, who denies attempted murder, sliced open her face and put the knife completely through her wrist and caused others wounds to her shoulders, leg and breasts.

Giving evidence behind a screen at St Albans Crown Court on Tuesday, the 44-year-old woman said: “He was swinging his arms like an orangutan. He was hitting me and hitting me. He was on top of me and I was trying to hold him off with my walking stick. He was making groaning noises.

“I was pleading with him. I did not know what on earth was going on. I said ‘What are you doing? What are you doing? over and over again. He wasn’t stopping he was just hitting me and hitting me. I was really confused. I thought he was going to kill me. I just though I was going to die.”

Opening the case prosecutor Peter Shaw said: “It was a vicious attack. The victim did her best to defend herself. She believed she was being subjected to repeated punches. At the end of the attack the assailant ran off. She saw blood and realised she had been stabbed.”

Mr Shaw said the most visually shocking wound was a “slice into her cheek”. The knife had also passed from one side of her wrist through to the other. She had stab wounds to her shoulder, upper left leg, lower right leg and to a breast.

Within an hour of the attack Simmonds himself had dialled 999 and said he had stabbed a woman in St Albans. The police went to his home where he was threatening to harm himself. Mr Shaw went on: “He was interviewed at the police station. He said he had been in the pub and got involved in a fight and stormed off. He got a knife from his flat and was looking for the person responsible for the earlier fight. He thought he saw the man concerned. It was a case of mistaken identity. He said he was very drunk at the time.”

The victim told the jury she had walked with a stick for the past four years because of rheumatoid arthritis. On the night of the attack she had returned from London where she had been visiting friends shortly after 11pm. She left St Albans Station and walked down Alma Road listening to music on her iPod.

A man, whom she later knew to be Simmonds, was standing outside the Great Northern Pub. She said: “He was pacing up and down outside the pub. He was staring at me. I looked at him and I crossed the road. I walked down Alma Cut.

“I felt Shane Simmonds running behind me. He jumped on me from behind and pulled my hood over my head. It covered my whole face. It completely covered me.

“I pulled the hood back and turned to face him and started to ask him what he was doing. I got no response. The next thing he pushed me onto the floor. I landed on my knee and face on the pavement.

“I turned over on to my back and had hold of my stick. He was hitting me. He was hunched over me.”

She said she was holding her stick across her chest in an attempt to fend him off and her screams were heard by a neighbour who shouted: “What’s going on?” out of a bedroom window.

Simmonds was then said to have got up and stamped on her upper arm before she saw him leave, “zig zagging” up the road.

The woman said she got up and realised she had been stabbed as blood poured down her arm and leg. An ambulance was called and she was given morphine.

She was first taken to Watford Hospital before being transferred to the Royal Free in London where she had plastic surgery on her face. Police recovered a knife at the scene of the attack.

Simmonds, previously of Artisan Crescent, St Albans, but now of Brandon Road, Thetford, Norfolk, denies attempted murder on the night of 4 October. The jury of eight men and four women have been told he has pleaded guilty to the lesser charged of causing grievous bodily harm with intent.

Mr Shaw said: “He admits he was the man who carried out the attack. The crown say the number of times he stabbed her proved that he must have had the intention to kill.”

The case is proceeding.