Law graduate Extinction Rebellion activist, 28, who killed her fiancé by stabbing him with a kitchen knife as he begged ‘I love you, please’ gets life

An Extinction Rebellion activist, who dreams of becoming a human rights lawyer, was sentenced to life in prison yesterday for stabbing her fiancé to death.

During a domestic fire, Lily Wallace, 28 – who was pregnant at the time – had followed 34-year-old Samuel Mayo into the street near their London home and stabbed him.

Witnesses heard his last, desperate words as he shouted repeatedly, “Please, Blaze. I love you, please Blaze.”

Samuel suffered a fatal 4 cm wound in Lower Richmond Road, Mortlake on July 18 last year. He bled to death around 9:45 p.m. as he begged motorists and passersby to call an ambulance.

Kingston-upon-Thames Crown Court unanimously convicted Wallace of murder and possession of an assault weapon after the three-week trial. She will serve a minimum of twenty-four years.

Judge Rajeev Shetty told Wallace, who was wearing a black Casper The Friendly Ghost sweatshirt and had her hair braided cornrows style, “You stabbed him once in the chest.”

“You stabbed him at a downward angle with enough force to send the blade through the cartilage of his ribcage and into the heart. He screamed for help and lost a lot of blood at that moment.

“Unlike the people who tried to help him, you did nothing and left the scene, letting him die and showing a total lack of remorse for stabbing him in the chest.

“He had a life plagued by heavy drug use like yours, but despite this he was loved by his family and well known in the area.

“It was a volatile relationship and he had been violent towards you and witnesses revealed a central theme of quarrels in the street and at home in which you were also the aggressor.”

Mr Mayo is said to have left their home with some belongings after the pair rowed in the backyard.

Both were under the influence of heroin, cocaine and cannabis tonight and had been rowing in Wallace’s one-bedroom flat in nearby Mullins Path.

Wallace claimed that Mr. Mayo had a sharpened wooden chopstick that she thought he wanted to use as a weapon.

The jury rejected Wallace’s claim that Mr. Mayo was armed and that she simply used the knife to fend him off to protect herself and her unborn child.

During the subsequent police investigation, no chopsticks were found in the area.

Judge Shetty said, “You followed him about six minutes later. You took a large knife with you and I completely disavow that you brought that in case things got violent and you needed to protect yourself.

“You kept that knife out of sight and in a rage and rage at being belittled or called ‘mean’ caught up with it at The Stag Brewery, Lower Richmond Road.

“He wasn’t a threat to you at all and he didn’t attack you or try to attack you and I dismiss this as excessive self-defense.

“You stabbed him in the middle of the chest where his heart was. There must have been an intent to kill.

“I sentence you to life imprisonment with a minimum of twenty-four years. That is no guarantee of release, you may never be released.’

Mr Mayo’s heartbroken mother, Sarah Johnstone, described him as a “kind, considerate” son, brother and uncle who “always made us laugh and nothing seemed to put him down.”

In her victim impact statement, read aloud by her other son Bailey Graham, she wrote: “When I heard my son Sam was killed it was absolutely devastating to me and my family.

“Going through the process was brutal for me and my family. We have to wake up every day knowing we won’t see Sam again.”

She added, “Our pain will never go away and the family will always be missing a piece.”

Wallace graduated from St. Mary’s University, Twickenham in 2017 with a law degree and was one month short of completing her Masters in Human Rights & Legal Practice at the University of Roehampton when arrested.

She had ambitions to work abroad as a human rights lawyer in Germany, Canada and Asia.

Wallace gave birth on March 30 after being transferred to St. George’s Hospital in custody and her older brother is currently caring for her daughter.

Her attorney Joe Stone KC told the court, “This is not a lady with a proven track record. She is not an experienced criminal, used to London prisons, quite the contrary.

“It wouldn’t be an exaggeration to say it will have a profound effect on her life now and at least for the next two decades,” added the KC, who described Wallace as “not a ruthless killer.”

CCTV footage showed Wallace deliberately following Mayo as she, armed with the knife in her pocket, overtook him outside the massive Stag brewery.

Prosecutor Corinne Bramwell urged the court to take a minimum of twenty-five years in prison. “This was a planned attack using a weapon. It was brought to the scene by Mrs. Wallace.

“The defendant intended to kill Mr. Mayo. She followed him for some distance armed with a knife and after catching up with him she stabbed him once in the heart with a sharp knife, without looking back.

“It was premeditated and she was under the influence of Class A drugs and the jury dismissed self-defense for an incident that lasted sixteen seconds.

“This wasn’t a moment in the middle of an attack, but as it turned out earlier, the argument that caused him to leave Mullins Path involved Mrs Wallace being the more aggressive and unpleasant party.”

Mr Mayo, who was eight stone, bled to death at the scene and when police arrived at 9.57pm they immediately recognized him as a local drug user, regularly begging outside Tesco and Mortlake train station.

He was taken to Kingston Hospital and pronounced dead at 10:33 p.m.

Police officers arrived at Wallace’s house at 1 a.m., but she didn’t give them the same explanation about the chopstick.

Two old unrelated assault charges against PC David Jones in North Warpole Way, Mortlake and Jessica Whiting in Mullins Path on 3 August 2020 were dropped by the prosecution.

The judge sentenced Wallace to four years concurrent with life imprisonment for the assault weapons charge.