Emadh Miah chased and lunged at Ghulam Sadiq - who was also 18 - in a "planned attack" that was metres from the victim's home in Leytonstone, east London.

He was found guilty of murdering Mr Sadiq at the Old Bailey in April.

Miah, from Solihull, had bought the weapon online using someone else's ID because he was underage at the time.

The attacker had travelled to London with his mother to see his grandfather - but during the visit, he rented a bike and concealed his identity.

Although the violent murder in daylight was captured on CCTV in August 2022, Miah wore a mask, gloves and a hood.

Miah was on bail at the time for attacking a 16-year-old boy with a hammer in March 2021 - and James Wood KC, defending, had told the court he was visiting his grandfather before the sentencing.

At Lewes Crown Court on Tuesday a statement was read on behalf of Mr Sadiq's mother Khalida Parveen before Miah's sentencing. She recalled seeing her son lying in a pool of blood outside a pizza shop.

She had written: "I'm here today for justice, we have lost our world, please don't let him do the same to anyone else.

"I'm haunted by the recurring nightmare of the horror Ghulam suffered. I blame myself for not being able to protect my child from such a cold-blooded individual."

Ms Parveen, a mother of two, said she and her younger son had kept mementoes, including his clothes and a note that said: "Don't worry, I'll clean my room when I get back."

Mr Sadiq was described as "very popular, passionate and great fun" - and an entrepreneurial young man who was always coming up with business ideas, including a premium platform for cleaning trainers.

The court was told that Miah had suffered post-traumatic stress disorder from violent incidents of bullying against him and has mild autism.

A statement written by the defendant that was read in court said: "I'm sorry for what I have done, I didn't mean for it to happen. I'm not good at writing so I will ask my mum to write out what I want to say, but for Ghulam's family I'm sorry for causing you so much pain."

Judge Christine Laing KC sentenced him to life in prison with a minimum term of 19 years.

He was also handed concurrent sentences for the earlier hammer attack, as well as possession of a hammer and bladed article.

While she took Miah's mental health issues into account, the judge said she was "quite satisfied he knew he was doing".

She added: "Although I have no doubt you intended to cause the maximum harm to Ghulam Sadiq, I will give you benefit of the doubt you didn't intend to kill him."

When the trial had ended in April this year, Judge Laing had condemned the "shocking" availability of dangerous weapons online - urging jurors to write to their MPs.

At the time of the conviction, the Metropolitan Police described it as "one of those rare cases where we have never been able to conclusively establish a motive for the crime".