Shocking CCTV has been released of the fatal attack on a millionaire banker who was killed in a row over his phone, after his family said they were “immensely disappointed” that the killer was not convicted of murder.

Paul Mason, 52, was attacked by a complete stranger, 34-year-old Steven Allan, as he walked through the West End on his way home from a meal with a friend at The Ivy.

Allan, who had been drinking, was consumed by a mistaken belief that his friend’s phone had been stolen by Mr Mason, and he delivered a series of blows to leave the victim lying unconscious in the ground in West Street, Soho.

Mr Mason, a highly respected banking executive who worked for the Qatar National Bank, suffered serious head injuries in the attack and died in hospital around six months later.

Allan admitted manslaughter and was acquitted by a jury of murder. At the Old Bailey on Thursday he was sentenced to three years and nine months in prison.

Mr Mason’s family said afterwards: “We are immensely disappointed that the jury did not all see the intent to cause serious harm that most people who saw the CCTV concluded.

“We really hoped he would get a life sentence, but we must try to accept the jury’s decision. At least he will be imprisoned for killing Paul and we can start to move forward a little.

“Words cannot express how traumatised and distressed we were when we were told about the attack on Paul, a senseless act of violence on an entirely innocent man simply making his way home from an evening out with friends.”

The attack happened on December 15, 2020, when Allan – a project site manager in Hyde Park – was standing on a street corner waiting for his friend.

He had developed an unfounded suspicion that his friend was about to be robbed and tried to call him, and then wrongly came to the conclusion that Mr Mason, who was randomly walking by, had stolen his phone.

Footage shows Mr Mason recoiling in shock as Allan first tried to grab the phone from him. The banking executive turned to walk away, but was pursued Allan who first knocked him to the ground and then delivered another blow which left Mr Mason prone and unconscious on the ground.

Judge Michael Topolski KC called it a “horror story” as he sentenced Allan, and was apologetic to Mr Mason’s family as he imposed a jail term that will see Allan set free within a year.

“I’m well aware the sentence I’ve just passed will seem like nothing to (Mr Mason’s) family”, he said.

“The circumstances that to the defendant causing the death of a perfectly respectable and wholly innocent stranger who happened to be passing by are as extraordinary as they are tragic”, said the judge.

“During the course of cross-examination in your trial, you expressed that all the thought that evening amounted to unsupported nonsense.

“You said you had taken leave of your senses and behaved out of character because you genuinely believed you had an anxiety and panic attack that evening.

“You will have to live with the knowledge for the rest of your life that you were responsible for taking that man’s life. The mystery that underlines the behaviour is why you went from a heightened state of anxiety to a man of violence in a matter of seconds.”

In a powerful victim impact statement, Mr Mason’s sister Rachel Mason revealed that their brother Simon had died from an overdose just three months after Mr Mason succumbed to his injuries in December 2020.

“You’ve broken my family for evermore. I’m overwhelmed with feelings of shock, disbelief and hatred towards you. How dare you take Paul’s life?”, she said.

“I just can’t comprehend someone doing this to another human being especially someone I loved so much.”

Ms Mason said they had to watch their brother on FaceTime as lay in a coma due to Covid restrictions, calling him a “remarkable, kind, decent, gentle soul who was so successful in every aspect of his life, highly regarded in his international banking career, loved dearly by his family.”

Holding up his mobile phone in court and looking directly at Allan, she said: “This is Paul’s phone. You killed him for this.”

“I hope you feel sick in the pit of your stomach every day for the rest of your life as you live with being a, in my mind, murderer.” Allan, from Hook in Hampshire, left the scene of the attack within a minute of knocking Mr Mason unconscious, as heroic nurses who were passing tended to the injured man.

Allan handed himself in the following day after seeing CCTV images of himself being circulated by the Met Police. He admitted manslaughter but denied murder, and was acquitted at two criminal trials.

“Paul Mason’s death tragically illustrates the consequences of resorting to physical violence”, said Detective Chief Inspector Wayne Jolley.

“Even where there is no murderous intent, there is no guarantee that a violent attack won’t result in death.

“Mr Mason’s family are devastated by this incident. Paul was an innocent victim of an unprovoked attack which resulted in a serious brain injury. They have had the unenviable experience of a trial and a retrial but have acted with dignity throughout. Our thoughts are very much with them today.”