A student who later stabbed his housemate to death was "terrified" by his victim saying they were "looking forward to killing him", a court has heard.

Zack Coughlan, 23, stabbed Jamie Collins, 21, at their home in Bristol on 8 April. Coughlan admits responsibility for the attack but denies murder on the grounds he feared for his life.

Sobbing while giving evidence during his trial at Bristol Crown Court, the defendant told the jury Collins insisted he meant his threat the day after making it, and said Coughlan locking his bedroom door "wasn't going to help".

Later that same day, Coughlan ambushed Collins, stabbing him 30 times and leaving him for dead, only to call police eight hours later.

Coughlan and Collins, who was originally from Swansea, were both final-year robotics students at the University of the West of England (UWE), and lived together in a house in Filton owned by the defendant.

CCTV footage was previously shown in court of Coughlan dressed in black and wearing a mask to ambush and stab Collins in their garden, before cycling away to dispose of the bloodstained evidence.

After returning home, Coughlan cooked a pizza, played online games with friends and then called police at 02:00.

In his evidence to the jury, Coughlan said he felt "horrible" about killing his former friend and lying to police.

He said he had a "good relationship" with Collins before he moved in, but tension grew, especially over the issue of rent.

When they eventually spoke about the rent, Coughlan said Collins was "more hostile than he had ever been".

"He said it was disgusting to charge your friends rent... I was shocked to be honest. He hadn't told me anything about this before," he said.

Coughlan said he reduced the rent to £500 and then to zero because his tenants were his friends and he "wanted to help".

But Coughlan said this did not fully diffuse tensions and Collins would talk about landlords and multinational corporations being to blame for social inequality.

He told the jury his criticism of landlords would sometimes become personal.

"He didn't feel that rent should be charged and there was a lot of inequality and that was a landlord's fault," Coughlan said.

"He mentioned he wanted to pour acid down Elon Musk's throat... This disturbed me quite deeply," he said.

"I thought he was my friend so I didn't want to believe that he meant any harm," Coughlan told the jury.

The defendant said by April their relationship was "pretty bad", as Collins was just ignoring him and all communication had broken down.

On 7 April, he decided to ask Collins to leave the house, which prompted a threat of violence, the court heard.

"I think he had a kitchen knife in his hand and he said he looked forward to killing me," he told the jury, prompting audible gasps in the public gallery from Collins' family.

"He said what I had done was disgusting and that I was scum and he was looking forward to killing people like me - I was so frightened.

"I went to my room," he told the court, in tears. "I hid under the covers and I locked my door," Coughlan added.

The defendant told the court he did not tell police because he did not think they would help him, due to what he said was their inaction in response to a recent report he had made about a group of men pulling a knife on him in his garden.

Coughlan said he tried speaking to Collins as he was leaving for university the next day.

"I wanted to believe what he said wasn't true, I had to understand if he meant what he said so I asked him," Coughlan said.

"And he said yes. And locking my door wasn't going to help."

"That was the last thing we ever said to each other," Coughlan said, adding he felt terrified and "didn't know what to do to protect himself".

Coughlan said he changed clothes and took a kitchen knife from his bedroom before he began pacing, trying to talk himself out of hurting Collins.

"I was contemplating killing Jamie because of the things he had said," Coughlan told the court.

"I just felt that I had to. I had no choice," he added.

Coughlan then waited for Collins to return home and ambushed him.

"I didn't hate him when he died. I just didn't know what to do," he told the jury.

The defendant said he then rode off on Collins' bike, before disposing of the knife.

"I couldn't accept the reality of any of it. I had to run away from everything and cast everything away," he told the court.

After disposing of his bloodstained clothes in a pond and buying some food, he returned home at about 21:00, but said he did not check on Collins or call police because he "couldn't face it all at that point".

Coughlan said he played video games on his return and put the bins out because he was "trying to cling to something to just bring some normality back".

After he called police at about 02:00, he said he lied to them about what had happened because he could "barely make sense" of it.

"I was so horrified and devastated by what I saw and I still was scared – that feeling didn't go away for days and days," he said.

The defendant said he did not realise he had stabbed Collins 32 times until later at the police station.

"I thought it was just a few times. I didn't think it was that bad," he told the jury.

Coughlan told the court he did not think Collins was dead when he left him.

He apologised for his actions, adding: "I hate everything about it. I wish none of it occurred."

The trial continues.

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