A gatecrashing teenager murdered a schoolboy with a martial arts weapon outside a Halloween party after being told to leave, a court was told.

Richard Martin, 19, went to the party with a friend and behaved in a way described by some revellers as “irritating and antagonistic”.

Victim Ricky Butler, 15, was smoking a cigarette with a friend outside the flat rented by his brother Steven when a row broke out.

During the altercation on the front steps, it is alleged that Ricky told Martin to “f*** off”.

Lewes Crown Court heard that Martin may have felt “injured pride” at the comment and left the party before returning shortly afterwards armed with a martial arts weapon.

Charles Miskin QC, prosecuting, said Martin went up to Ricky and said: “Don’t tell me to f*** off, you ****” before attacking him with the weapon, fracturing his skull.

Mr Miskin told the jury: “Ricky tried to protect himself and in due course a friend joined in to try to prevent further injury to Ricky, and in so doing found himself injured as well.

“Both young men were hit several times round the head.

“The attack suddenly stopped and Richard Martin left but told a witness ‘You bitch. I’ll shoot you as I know who you are’.”

Following the attack in Gorringes Brook, Horsham, Ricky was able to stagger back inside the flat and talk to his brother, but he soon lapsed into unconsciousness, from which he never recovered.

He was taken to East Surrey Hospital in Redhill, Surrey, then transferred to St George’s Hospital in Tooting, south west London, where he died from bleeding to the skull later that day, November 3 last year.

Mr Miskin told the jury of nine men and three women: “It was established that the attacker was called Richard and he had attended the party with Nathan Gray, and Nathan Gray pointed out the attacker’s address to the police.

“In fact Nathan Gray had spoken to Richard Martin and he denied doing anything at all.

Richard Martin was arrested at the time on suspicion of attempted murder. He was taken to the police station and was totally uncooperative, refusing to provide DNA samples or take part in an identity parade.

“Subsequently, witnesses identified him and he was charged with the murder of Ricky Butler on November 4.”

Police were initially unable to find the nunchakus weapon used to kill Ricky but Mr Miskin said defence solicitors later wrote to the police stating that it was concealed behind a pub in the town.

Unemployed Martin, of Heath Way, Horsham, denies murder and wounding with intent.

Mr Miskin said the defence does not dispute that Martin was responsible for Ricky’s death. But he said it would be up to the jury to decide whether Martin deliberately intended to kill Ricky or whether he merely aimed to cause him serious bodily harm.

Mr Miskin said: “It’s the prosecution’s case that the injuries that the two young men sustained were the result of a wholly unlawful attack by Richard Martin, and that, as a result, Richard Martin is guilty of the murder of one and guilty of unlawfully wounding the other.”

The court heard Martin gatecrashed the party hosted by Ricky's brother Steven and his girlfriend on November 2 last year.

A teenager, now 17, who was sitting chatting to Ricky tried to protect his friend from the blows and was also injured. He suffered a broken finger and needed stitches to a head wound.

Ricky, of Leith View Road, Roffey, Horsham, was a pupil at The Forest School.

Ricky's friend, who tried to shield him during the attack, told police Ricky had been a “bit mouthy” to Martin as he left the party.

In an interview with detectives recorded shortly after the attack and shown to the jury, he said: “About five minutes later he came back with a pair of nunchakus and took a full swing at Ricky. I tried to lean over Ricky.”

He said he heard the weapon crack as it hit his friend’s head.

“Ricky fell backwards. This guy hit him a couple of times. It happened quickly. I tried to get in between him to try to stop him from hitting Ricky. He didn't stop so I got hit a couple of times.

“He was being aggressive. I can’t remember what he was saying. He was swearing.”

The attack stopped and after Martin fled on a bicycle he went inside the flat with Ricky, who collapsed. He said: “There was loads of blood coming off my head, dripping down my shirt.”

The trial continues.