A 17-year-old boy has been locked up for life for stabbing a keen boxer to death during a street robbery.

The youth was one of a group who snatched 25-year-old Wilham Mendes' bag as he walked home from work in Tottenham on December 22 last year.

The restaurant porter was chased into an alleyway where he was stabbed repeatedly with a large knife.

He suffered "catastrophic" injuries and bled to death as the boys ran off with his possessions, the Old Bailey heard.

Afterwards, two of the youths, aged 17, were seen to "fist bump" in celebration, the court heard.

Prosecutor Oliver Glasgow QC told jurors that Portuguese national Mr Mendes was stabbed out of "simple aggression and blood lust".

Judge Angela Rafferty QC described the death of "hard-working" Mr Mendes as "brutal and senseless".

She said: "The carrying and use of knives on our streets is a blight on our society."

The jury heard how police were called to a stabbing three days before Christmas at around 1.20am. 

Wilham Mendes was found with stab injuries to the chest and stomach.

He was taken by ambulance to the Royal London Hospital, but despite the efforts of medical professionals, Mendes was pronounced dead in hospital at 2.13am.

Wilham was a Portuguese national who had been living in the UK since 2015, most recently in Tottenham. His next of kin were located and notified in Portugal.

A 17-year-old boy pleaded guilty mid-trial to Mr Mendes's murder and was also convicted of two robberies and possessing two knives.

The defendant, who had 21 previous convictions, was detained at Her Majesty's pleasure for a minimum of 16-and-a-half years.

Another 17-year-old boy, who cannot be identified, was locked up for 10 years for his part in the killing.

He pleaded guilty to manslaughter and possession of a knife and was found guilty of Mr Mendes's robbery.

A 16-year-old boy was locked up for two-and-a-half years having admitted the robbery of Mr Mendes and the robbery of another man earlier that evening.

Another 16-year-old was handed a youth rehabilitation order with two years' supervision and a three-month curfew having been found guilty of Mr Mendes's robbery.

Extra dock officers in riot gear were drafted into the dock of the Old Bailey for the sentencing.

After the first two defendants were sent down, screams, shouts and loud banging noises could be heard from the cells.

DS Devan Taylor said: “This was a tragic case. Wilham Mendes was returning from work when he was attacked. He was an outstanding young man who came to the UK in furtherance of a promising career.

"He was in the prime of his life with a bright future ahead of him, only for that future to be snatched away by a group of boys who had set out that night to rob and steal from anyone who had the misfortune of crossing their paths.

“Their behaviour was truly shocking and they showed no regard for another person’s life that night.

“But it doesn’t end there. The Mendes family now have to live with his loss and the four defendants will live the remainder of their lives with the stigma of criminal record, and the death of a man on their conscience.“