A teenage robber has been locked up for life after a 17-year-old weapons dealer was fatally stabbed on a towpath and pushed into a canal.

Elijah Gokool-Mely, 18, attacked Victor Lee near the Grand Union Canal in Willesden Junction, west London, on the afternoon of June 23 last year.

The defendant wanted to rob Victor of his bicycle and a rucksack said to contain a stash of knives the victim had bought online to trade.

Earlier that day, the defendant had bought a crossbow from Victor and had arranged to meet him to buy knives, even though he had no money to pay for them.

In those few seconds when you stabbed Victor you took away his most precious possession, his life

Two men living in nearby houseboats acted quickly to pull Victor from the canal water but he bled to death at the scene.

After a trial at the Old Bailey, Gokool-Mely was found guilty of murder and robbery.

On Friday, Gokool-Mely, of Shepherds Bush, west London, was detained at His Majesty’s pleasure for a minimum term of 20 years.

Judge Peter Rook KC said it was a “vicious attack with three blows, at least one of them with severe force”.

He told the defendant: “You stabbed him twice in the back in quick succession and once in the chest.

“In those few seconds when you stabbed Victor you took away his most precious possession, his life.”

He said Victor would not have appreciated the risk he was taking when he agreed to meet Gokool-Mely.

The judge told the defendant: “Earlier that day you bought a crossbow from Victor at the same location and arrangements had been made to meet him again to buy knives.”

The court heard the defendant had a previous conviction for having a machete and was on police bail at the time.

Victor, from North Acton, was described by his family as shy, introspective, easily manipulated and at risk of being exploited by others.

My son Victor remains alive in my heart and in the hearts of those who loved him. I never wish anyone go through this, never

His mother Kristina Lee described the “most terrible and unbearable pain” of losing him, saying family, loved ones and friends had been “shocked by this brutal murder”.

She told the court: “My son Victor remains alive in my heart and in the hearts of those who loved him. I never wish anyone go through this, never.”

She said her son’s dream was to travel to the US with her.

She added: “My son Victor matters, every living person matters.”

The court heard that Victor had met his killer having developed an interest in buying weapons online which he wanted to sell for profit.

Police believe he did not fully understand the harm others could cause with the weapons.

The defendant was linked to the murder by analysis of mobile phones and CCTV as well as witnesses and forensic evidence.

A knife with the victim’s blood on it and Gokool-Mely’s DNA was recovered from his home.

Detective Chief Inspector Brian Howie, of Scotland Yard, said: “Victor was a young man who was not directly involved with gangs or criminality – he had an interest in buying, fixing and selling bikes.

“He had energy and drive but sadly not enough wisdom. His family have told me that he had an inability to properly assess situations, people or threats.

It will forever be a source of regret to me that this vulnerable but independent young man was able to buy weapons online simply by altering the date of birth in his passport

“When Victor crossed paths with the defendant, he took advantage of him and ultimately subjected him to a sudden, unprovoked and shockingly violent assault.

“Having worked so intensely on this case – speaking to Victor’s family and thinking about his life and tragic death – it will forever be a source of regret to me that this vulnerable but independent young man was able to buy weapons online simply by altering the date of birth in his passport.

“Having previously purchased knives, Victor bought a crossbow online in the days before he was killed, and seems to have sold this to his killer at around 3pm on the day of his murder.

“He was robbed and murdered when seeking to sell knives to him later that day.

“Apparently unable to grasp the devastating consequences of his actions, he probably regarded this as an interesting scheme to make some money. But, having met his killer after arranging to sell the weapons via Snapchat, this scheme sparked the events which cost him his life.”

In mitigation it was said that Gokool-Mely had remorse and wished to “turn the clock back”.

However, police highlighted a notebook recovered from his prison cell last December containing handwritten rhymes.

One said: “Everyone on at the 8pm news, ITV, Sky, BBC; Broadcasting the stabbing I done.

“The people that knew me changed their views. I tried my best to leave no clues. My door got boomed my mum’s confused.

“No I don’t feel sorry for the yute.”

Another line said: “On the phone I’m saying I’m innocent; hop of (sic) the call then laugh in my cell.

“Aye officer no I didn’t kill him; just stabbed him sent him heaven or hell.”

Two other youths, aged 14 and 15 at the time of the attack, were cleared of murder and robbery after the trial.