Grace O'Malley-Kumar, 19, was killed in the knife attacks in June, alongside Barnaby Webber. They had been returning from a night out celebrating the end of their exams.

The killer, Valdo Calocane, also stabbed school caretaker Ian Coates to death as he made his way to work.

Calocane admitted killing Grace, Barnaby and Ian on the basis of diminished responsibility, a plea which the Crown Prosecution Service has now accepted.

"Grace's last moments were in pain and that's something that really hurts me to think about and she was a hero, that was her character", her brother, James, 17, told Sky News.

"She tried her best to save her friend. That was how Grace lost her life in the most vulnerable manner. She would never leave a friend, never, and that was very evident from her last moments. She passed fighting."

Calocane, 32, also known as Adam Mendes, had a history of mental illness, and even tried to hand himself into the MI5 headquarters in London, believing the British security services were controlling him.

Grace's family had hoped Calocane would face a murder trial.

"It's very hard to accept for a father and I'm sure for a brother, but we have faith in the legal system," Grace's dad, Dr Sanjoy Kumar, said.

"We have faith in the judiciary and have faith in the court. And we hope that they do Grace justice."

Knife crime 'epidemic'

He called for tougher government action on knife crime, which he described as an "epidemic".

"It's at epidemic proportions and yet lawmakers seem to be doing nothing about it," Mr Kumar said.

"I think we really need to start looking at knife crime. Knives are not an offensive weapon, they are a lethal weapon and as such, I think laws need to be changed and ultimately there must be a deterrent.

"If there isn't an appropriate deterrent for carrying knives then it's just going to carry on, our lawmakers need to look at knife legislation as soon as possible.

"We cannot just have a slap on the wrist for the first time that you carry a knife and get caught with it."

Grace's brother said he could "never forgive" Calocane for killing her.

'I really miss her'

"She was just the best sister I could have asked for, she was always there for me as a shoulder to cry on and to quietly listen. She had my best interests at heart all the time," he told Sky News.

"Her smile was so contagious, I really miss her. Knowing that I'll never see that again it's something that really hurts me, she was such a joyous person to be around.

"Her laughter, her excitement, she had such an unmatched zest for life. She was honestly so perfect."

"I think the loss that we've suffered of losing Grace has been a loss to the country.

"She was someone who served the country in her life, playing [hockey] for England, played for England under 16s, under 18s for two years.

"She had ambitions of serving as a medic in the armed forces and again serving the country and she was a person who had a priority of contributing to the community during COVID.

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"She was trained as a vaccinator and she rode on her Vespa to the vaccination clinic to vaccinate hundreds of people against COVID.

"She put herself at risk to benefit others and help the community get in a better position and to take that away from us it's completely unfathomable.

"I will never forgive him. He's taken away my older sister and one day when my parents are gone I'm now going to be left on my own. I won't have my sister. My future children won't have an aunt, they won't have cousins."

Remembering Grace

Dr Kumar said it has been "a brutal journey" since her death.

The family are setting up a foundation in her memory with the help of her childhood friend, Alex Simpson.

Mr Simpson said its aim was to "emulate the love and care that Grace gave to this world, 'be more like Grace' is our motto - our aim is make sure no one is left out and everyone is happy".

Funds raised will go to furthering causes that Grace supported like sport and education and they also plan to lobby the government about knife crime.

"I find myself completely lost since the 13th [June]," James told Sky News.

"I haven't had my best friend to go to. I haven't had an older sister to call. She hasn't been there to pick up the phone to me and all I can do now is take comfort in the slightest thing - I sleep with her university hockey top on my pillow and I wear her clothes.

"That's how I try and connect with Grace, I have her earring in now which I always keep in. And again, it's a part of her and that's how I try and get as close as I can to her."