Braedan Bubb-Clarke told the jury he was 17 when he attended the party in Pack Road, south-west London, with his friends, including shooting victim Josue Silva.

He said that after a dispute and some shouting between partygoers and his peers, he testified about what he saw: “When I got to the altercation it was about to end… I remember telling them to leave.”

Moments later, other people warned him about possible trouble and that someone was seen with a machete at the location, saying: “With the calls I received I thought I was in danger, it was like a shock to me.”

He went on to say, “I ran into the woods…I was very worried for my safety and the safety of my friends.”

Bubb-Clarke added: “After the phone call ended, I remember hearing a loud bang, like a gunshot. My mind was racing, I felt like I was still in danger.”

Silva, 18, was found with a gunshot wound to the abdomen and was later pronounced dead at the hospital.

Days later, Emily Altmann, 22, and Carlos Guerra Guerra, 23, were charged in the case. Both have pleaded not guilty to second-degree murder and assault causing bodily injury.

The witness told the jury that while he was hiding he was so scared that he called his father to come pick him up. When he emerged, he was confronted by police officers.

Bubb-Clarke said when she called her father, “I told him I thought someone had been shot and told him to come get me.”

When he saw the officers, he said: “The police had guns and guns, I was shocked at exactly the same time I heard my dad call my name, I didn’t say anything because I was scared.”

Later, during cross-examination by the defense, Bubb-Clarke was asked why he didn’t call 911 and he responded in part by saying, “When I was out with my dad I panicked and had a hard time breathing.”

Wednesday marked the 14th day of evidence that will be heard at the trial.