This is the moment that a man with Asperger’s Syndrome was killed with a single punch to the head.

Andrew Young died after 20-year-old Lewis Gill, of Ridge Road, Sutton, lashed out in November last year.

The defendant, who was arrested in Croydon and admitted manslaughter at Winchester Crown Court last month, struck Mr Young after the victim exchanged words with an acquaintance.

Victor Ibitoye had been riding a pedal cycle along Charminster Road in Bournemouth on November 6 last year when he was confronted by Mr Young, who said it was a "dangerous" activity.

Mr Ibitoye was walking next to Gill's ex-girlfriend, Wendy Cagua-Rodriguez, while the defendant walked behind.

He threw a single punch, connecting with Mr Young's temple, after hearing the victim say to Mr Ibitoye: "Why don't you go back to the jungle?"

Mr Young collapsed onto the road behind him and died the next day, November 7, at Southampton General Hospital.

Warning: This CCTV footage contains graphic scenes of a violent incident

This CCTV footage was shown at Salisbury Crown Court on Friday as Gill was sentenced for manslaughter.

In it, the victim, who is circled in yellow, is struck by Gill, circled in red.

Mr Young’s mother Pamela was heard to gasp as she saw the footage for the first time.

Sentencing Gill to four-and-a-half years in prison, Judge Keith Cutler said: “You threw a forceful and vicious punch at [Mr Young].

“He clearly was not any physical threat.”

Gill was sentenced to four years for manslaughter, and two three-month prison terms for run consecutively for committing the offence while on a suspended sentence and for handling stolen goods.