A Cambridge-educated actuary who murdered an Odiham chef with a spear gun and a carving knife because the victim's sister had dumped him has been jailed for at least 23 years.

Andrew Morris, 30, a brilliant mathematician who landed a £120,000-a-year job after university and was said to believe himself to be superior to other people, was convicted of murder on May 23 after a trial at the Old Bailey.

He was sentenced on Friday and told he would be jailed for life with a minimum term of 23 years.

When his then-girlfriend Michelle Stangroom finished with him, Morris blamed her brother Henry, 21, a talented chef working at the Criterion restaurant, and brutally murdered him as he slept on October 17 last year.

Psychiatrists who examined Morris said he may have done so in order to hurt Ms Stangroom.

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Before killing Mr Stangroom, he sacrificed Michelle's pet hamster - and even filmed himself doing it.

Morris fired a diver's harpoon gun at Mr Stangroom's head before repeatedly stabbing him in the chest with a kitchen knife.

He then turned the first weapon on himself and was found by police 18 hours later in the bath with a harpoon sticking out of his neck, having apparently attempted to slash his wrists.

Morris claimed he acted in self-defence when he was attacked by Mr Stangroom, who had accused him of stalking his sister, and that he was mentally ill.

'Deliberate, planned killing'

He sighed heavily in the dock while judge Wendy Joseph QC sentenced him.

She said: "This was a deliberate, planned killing, planned well in advance, amounting almost to an execution, on a man who at the time of the initial attack must have been asleep in his own bed.

"The only motive raised is that you set out to kill Henry Stangroom because he was the dearly beloved brother of Michelle who had left you, and because he either would not assist you in getting her back or was positively obstructing that possibility.

"I am quite satisfied that you have studied over and over again the papers in this case as you studied for your exams and that you have prepared a defence that sought to account for every facet of the Crown's case, right down to a bloodied sock print.

"What I have seen over the weeks of the trial were sustained attempts to manipulate the situation, most clearly by turning in the witness box and directly addressing Henry's parents and sister as they sat in court.

"Nothing I do by way of sentence can make up in any way for the loss of their child."

Henry Stangroom
Henry Stangroom

Mr Stangroom's mother and father, who were in court for every day of the trial, sat silently as the sentence was passed.

During the trial, the court heard that Morris loved designer watches and powerful motorbikes and spent much of his salary on status symbols, but beneath his professionalism he was a narcissist who could not believe any woman would have the audacity to reject him.

Ruth Owen, a former girlfriend, said he would ruin her belongings whenever they had an argument.

Morris became a father when he got another girlfriend pregnant, but abandoned her and his son to begin his affair with Michelle.

They moved into a flat in Lavender Sweep, Battersea, in September 2012 and her brother moved in with them three months later.

All three were drug users and took cocaine and nitrous oxide, the court heard. Morris was also suffering from depression and panic attacks.

He became violent towards Michelle, who eventually moved out, and Morris turned his anger on Mr Stangroom.

Mental illness claims

Before the murder, Morris researched 'horror speargun accident', 'speargun in heart' and 'how to kill someone in their sleep' on the internet. He also researched how to use mental illness as a defence in court.

Prosecutors claimed he did not intend to kill himself afterwards and knew he would be found by an estate agent who was due to call at the flat.

Police broke in when concerned relatives could not get in touch with Mr Stangroom and found the young chef lying on his blood-soaked mattress.

Michelle's pet hamster was missing from its cage and the mystery was explained when detectives saw footage of Morris squeezing the dying animal in his fist until the animal's eyes bulged from its sockets.

His claims of mental illness were rejected by top psychiatrist Dr Philip Joseph, who has examined some of the country's most notorious killers.

Dr Joseph said: "When he feels rejected or jealous or his emotional needs are not met, he can respond with petulant, immature or aggressive behaviour."

Speaking after Morris was told he would be getting a life sentence, Mr Stangroom's father Jerry said no jail term would be enough.

"There can be no justice for our son and brother, nothing will bring him back. Such a wonderful boy, we miss him so much," he said.

"The evidence has proved this was a premeditated murder whilst he was asleep by a coward hiding behind diminished responsibility.

"We will never be able to come to terms with the loss of Henry, we will never be able to move on.

"It’s impossible not to think of the terror he must have felt being woken with a spear gun wound to the head and then to be faced with the man he looked up to like an older brother, turned into a maniac with a knife. He would have been in no position to defend himself.”