Kallum Warwick got on a bus to Tilehurst at about 4am after a night out at Walkabout in Reading town centre in May last year when he saw a man sitting on the top deck on his iPhone.

The 21-year-old followed the man off the bus and struck up a conversation, but Reading Crown Court heard on Friday that the conversation quickly became hostile, with Warwick telling his victim he had to rob people to survive, and how he had been to prison and owned guns. The apprentice bricklayer then attacked him, punching him and ordering him to lie on the ground and empty his pockets before kicking him unconscious.

Warwick, of Brunswick Street, denied one count of robbery but was found guilty by a jury at Reading Crown Court following a three-day trial in August.

Michael Orsulik, defending, appealed for a suspended sentence, claiming Warwick has turned his life around since the birth of his son four months ago.

He said: “I know it is a well-used cliché but he has grown up a lot. He has met his partner, they have a good stable relationship. But over and above that Mr Warwick also has perhaps the best incentive that anyone can have to change his way of life and stay out of trouble — he is determined to be a good father.

“There are a lot of positives in this young man’s life. He has every reason to stay out of trouble in the future and lead a decent, honest, proactive, law-abiding life. He has never been to prison before, he is extremely fearful of a custodial sentence.”

But Judge Nicholas Wood told Warwick that although he could reduce the sentence to three years based on his age at the time of the offence, good character references and the fact he will be separated from his partner and young son, he could not suspend it.

He said: “The victim in the case was disorientated, mainly because he was lost. You became aggressive, you threatened him, you threatened to stab him, you hit him in the face, you punched him, ordered him to go on the ground or you would kill him. He emptied his pockets and you kicked him unconscious. This is not a case where I can suspend a sentence of imprisonment.”

Warwick, who was wearing a white shirt, grey trousers and tie and a black jacket, held is head in his hands and burst into tears as he was escorted from the court room and his racking sobs could be heard even after the door of the dock closed behind him.