A teenager's hand was chopped off in a "savage" knife attack as he curled up on a grass verge to protect himself, a jury heard.

Tyler Stevens, then 18, was struck six or seven times by the blade, with one blow completely severing his left hand.

The hand was found later in the street by a police officer. Doctors tried to reattach it, but their efforts came to nothing, St Albans crown court was told on Tuesday.

The prosecution allege the knifeman was Che Ambe, 21, of Caractacus Cottage View, Watford, who denies causing grievous bodily harm with intent.

Prosecutor Simon Wilshire told the jury of six men and six women that Tyler Stevens was attacked with a machete or large knife in Long Elms, Abbots Langley, on the evening of Sunday, February 10.

Mr Stevens, now 19, had been at a friend's house in Abbots Langley. Shortly before 9pm the two went to the local Spar shop where Mr Stevens bought a bottle of brandy.

They were on the way back to the house when a moped ridden by Che Ambe approached them.

Mr Wilshire said all three knew each other and did not get on. As soon as they saw Che Ambe, the other two started to run. The friend ran to his home, but Tyler Stevens slipped.

He added: "He got up and ran between two vans, but slipped again. He fell onto the grass verge. Che Ambe started attacking him with a machete or a similar weapon.

"He was hit some six or seven times as he was curled up on the ground, trying to defend himself.

"The attack was as brief as it was savage - one completely severed Tyler Steven's left hand," said Mr Wilshire.

Tyler Stevens did not realise his hand was severed until the attack stopped and Ambe fled, said the prosecutor.

The victim made his way to his friend's house and emergency services were called.

One police officer found his hand on a grass verge. Another officer found a knife on the opposite side of the road. This knife was not the one used to attack Tyler Stevens, but was one the victim said he was carrying for his own protection.

Tyler Stevens told police that the recovered knife must have fallen from the waistband of his trousers as his ran.

Che Ambe was spotted afterwards on a moped and was arrested after the police deployed a 'stinger,' which punctured its tyres.

The prosecutor said that when questioned the next day, Che Ambe said he was not there. But the jury was told that in a defence statement he now says he was acting in self-defence after Tyler Stevens produced a knife and waved it at him.

In a police interview played to the jury today (Wednesday) Tyler Stevens said Che Ambe arrived on a moped and said: "What's good?"

Tyler Stevens said: "We just ran - I knew he was looking for us. It was for stuff I had been dragged into. It was nothing to do with me."

When he slipped over on the grass verge he said he could clearly see Che Ambe's face in a motorcycle helmet, which had no visor.

He said: "I could see his face through the helmet. I can picture it."

Asked to describe the attack, he said: "I thought I was going to die. It was a big long knife - he was hitting me constantly. It was a long knife. It was either a machete or a big sword thing.

"He hit me six or seven times.

"I don't why it stopped - maybe he saw my hand come off and thought that was too much.

"I was screaming."

He said he made his way to his friend's house. When the door was answered, he said: "I said 'Che's chopped my hand off.'"

Mr Stevens said he suffered nightmares about the attack.

But under cross-examination by Stephen Cooke, defending, Mr Stevens denied that at the end of January - a week and half before his hand was chopped off - he and his friends had themselves chased Ambe.

Mr Cooke put it to Mr Stevens that on the night of the attack, he had pulled out a knife. Tyler Stevens said: "That is incorrect. It is not true."

He denied that he lunged towards Che Ambe with his knife.

Mr Stevens also denied he was standing up and put his hand in front of his leg when it was chopped off. He said: "I was on the floor when he was swinging at me."

The case continues.