A boy accused of fatally stabbing a market trader in a row over a stolen watch later denied "poking" the victim to his friends, a court heard today.

Rashid Naeem was knifed in the chest during a struggle near his stall in Queen's Market in Green Street, east London, in February, the Old Bailey was told.

Three teenagers - two aged 15 and one 16-year-old - have gone on trial accused of murdering the 29-year-old. They cannot be named for legal reasons.

The fatal injury was inflicted after Mr Naeem and his brother challenged the boys to give back a watch one of them had stolen minutes earlier, the court heard.

In his evidence, the 16-year-old boy admitted he "stupidly" stole a watch from Mr Naeem's stall but did not think he would get in trouble because it was only worth about £15.

He said: "I did not think they would be bothered because I knew it was silly to take a watch and maybe they thought it was just a little watch and they would not call the police."

But the next time they saw Mr Naeem on the market, the victim grappled with one of the 15-year-old boys who called for help, the court heard.

The witness said he went to pull his friend off and landed a punch on the market trader's arm in the process.

After they ran off, he said he saw the other 15-year-old, who told him their friend had stabbed the market trader.

"He said he thought (the boy) poked the guy and I said I did not think he did," the witness said.

Later they all met up in the witness's bedroom where he confronted the other youth about what happened.

He said: "I asked him did you poke the guy? He said 'no I don't think so, it did not go in'."

The witness said he became "angry", adding: "I called him stupid and I told him why. I was shocked."

But he said he did not think any of them were in any serious trouble at the time and they spent the afternoon watching television together.

Earlier in the trial, Sean Larkin QC, prosecuting, said one of the 15-year-old defendants does not dispute that he was responsible for the victim's death, but his main defence was expected to be that he acted in lawful self-defence.

The other two teenagers are charged with murder on the grounds that they were part of the "joint enterprise" and provided "strength in numbers", the court heard.

All three deny murder, while the 15-year-old who did not inflict the fatal wound denies possessing a knife.

The trial continues.