Emeli Sande's ex-boyfriend and rapper shouted 'I've been stabbed' before he collapsed on the floor at a Jubilee weekend party and died, a court heard.
Security guard Laurie John-Phillip, 33, is accused of murdering the rapper 'Hypo', whose real name was Lamar Jackson, on June 3 last year.
The Old Bailey was told 400 to 500 people descended on the 'really busy' party held in a marquee at Woodford Town Football Club in east London.
It was promoted as a 45th birthday party by an entertainment company and tickets were sold for £50.
The court heard Mr Jackson, 39, was 'well known' where he lived in Hackney, east London.
Rapper Hypo, whose real name is Lamar Jackson, 39 (pictured right) died after collapsing during a party in East London
Laurie John-Phillip, 33 was on duty as a security guard at the party
He dated Ms Sande, whose album Our Version Of Events topped the charts for 10 non-consecutive weeks in 2012, for a year before they split in 2017.
The defendant, whose nickname is 'Bigga', arrived at the party for his shift at around 4pm on June 2 last year - the weekend of the late Queen's Platinum Jubilee - while Mr Jackson turned up four hours later in a black Bentley being driven by his friend Obi Benson-Okpala.
CCTV showed an altercation appeared to take place between the defendant and Mr Jackson at around 10.30pm, which also involved the defendant's cousin Kieron Ceasar, whose nickname is 'Tiny', the court heard.
Once the lights had come on at around midnight and people had begun to leave, Mr Benson-Okpala heard a woman shout out that someone had been stabbed, jurors were told.
As he looked to his right he saw his friend Mr Jackson collapsing slowly onto his back and onto the ground, the prosecution said.
He joined the many people who rushed to help, calling 999 and at one point he went to get his car to take his friend to hospital as the ambulance was taking a long time to arrive, the trial was told.
Witness Graeme McLean was standing near the stage at around midnight when he became aware of a commotion involving around 20 people on the left of the stage, which appeared to end when the music stopped, abuse the jury heard.
As he left, he heard women screaming and saw a man on the ground outside the marquee, the court heard.
Mr McLean then saw someone jump forward from behind Mr Jackson and strike him on the upper left part of his chest before he shouted 'I've been stabbed', jurors were told.
A blood stain the size of a snooker ball formed on his clothes before he dropped to the ground, the prosecution said.
Mr McLean saw a closed fist but did not see any knife, the court heard. Jurors were told the alleged attack was not caught on CCTV.
The defendant left the venue 'as quickly as he could', pushing through crowds alongside his cousin and another man called Jalani Francis-Coa before fleeing in a car, the hearing was told.
Ambulance crews arrived at 12.22am on June 3 last year but Mr Jackson had stopped breathing and he was pronounced dead at 12.44am.
He is believed to have been stabbed at 12.07am, the court heard. A post-mortem examination carried out by Dr Simon Poole recorded his cause of death as sharp force trauma to the chest.
Mr Jackson (pictured) had an altercation with John-Phillip at around 10.30pm, CCTV footage showed, the court heard
John-Phillip, admitted to killing Mr Jackson (pictured) but claimed he acted in self defence
The defendant handed himself in to police and in three subsequent interviews, he spoke only to provide a prepared statement which said 'I did not murder Lamar Jackson' and to give a description of himself.
He did not answer any questions, jurors heard. Prosecutor Brian O'Neill KC told jurors: 'When you have heard the evidence, you can be sure that this was an unlawful attack by one man, this defendant, who was armed with a knife, upon another man who was unarmed.
'Accordingly, you can be sure and will be sure that this was an unlawful attack and that this was murder.'
John-Phillip, from Enfield in North London, admits killing Mr Jackson but claims he acted in lawful self-defence.
The defendant, dressed in an open white shirt and black trousers, did not speak at all during the hearing. The trial continues.
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