Trevor Gibbon stabbed next-door neighbour Alison Morrison 40 times on her way to work, after harrassing her family over several years

A “bad neighbour” who repeatedly stabbed the woman living next door in a “merciless act of vengeance” over a long-running petty dispute has been jailed for life with a minimum of 28 years.

Satellite TV engineer Trevor Gibbon, 48, armed himself with two knives and ambushed Alison Morrison, 45, from behind as she walked to the station on her way to work on 18 December last year.

He stabbed her 40 times on the day after he was handed a restraining order, having pleaded guilty to harassing Morrison and her family since they moved next door.

As she lay dying in the street, Morrison, a senior manager at consumer association Which?, repeatedly named her attacker, telling residents who had come to help: “Trevor Gibbon did this to me.”

The killer fled in his Mercedes but was picked up later the same morning 100 miles away in Lincolnshire. As he was arrested, he told officers: “It was over a neighbour dispute.”

Gibbon, who is originally from Birmingham, denied murder but admitted the killing on the basis that he was “suffering from an abnormality of mental functioning”. But the jury rejected his defence and found him guilty on Friday after two days of deliberations.

Sentencing Gibbon on Tuesday, judge Timothy Pontius said: “This was not a frenzied loss of control on the defendant’s part but a merciless act of vengeance indubitably with the intent to kill Alison Morrison in the forefront of his mind.

“This brutal murder robbed a close-knit family of a devoted and caring wife, mother, sister and aunt. A woman the victim impact statements make movingly clear with a zest for life and enthusiasm for her responsible and stimulating job.

“As a result her family have been left devastated and the devastating effects on the relationship between her husband and her son may take a very long time to repair.”

Earlier, in mitigation, Francis FitzGibbon QC said Gibbon was horrified and deeply sorry for what he had done. The lawyer said: “It is so wholly out of character that he and his friends and family are at a loss. No one could have guessed someone flashing his lights, banging on his fence, being a bad neighbour, could have done something like this.”

The court had heard the trouble dated back to 2011 when Morrison, her husband Cedric and their teenage son moved next door to Gibbon and his partner in Windsor Crescent, Harrow, north-west London.

Almost immediately, Gibbon complained about the noise from the boy’s skateboard and, despite the Morrisons’ attempts to placate him, nothing seemed to satisfy him.

Gibbon went on to harass and threaten Morrison by trapping her in her car, banging dustbin lids loudly at 6am below her window and repeatedly flashing his car lights. The situation came to a head in October last year, when Gibbon followed the family on their way to work and stopped and stared at them in his car in an “eerie prequel” of what was to come.

He was charged with harassing the family between 1 August 2012 and 31 October 2014 and admitted the offence at the magistrates’ court the day before the killing.

Morrison had complained of the “constant unending harassment”. The jury was shown a hand-written statement made days before the killing in which she said: “It got so bad that I could not sleep properly as I felt it would never end.”

Gibbon wept as he told the jury of the running “tit-for-tat” dispute he had waged with his neighbours. He described being “hazy” when he attacked Morrison and could not remember what was running through his mind.

Following his conviction, Morrison’s husband Cedric told the court: “Alison was my best friend, my soul mate, the soul of our home and the breadwinner to the household. Alison’s death will always be beyond my comprehension because she died for nothing in the cruellest way possible at the hands of our neighbour. A bright light has been extinguished forever.”

He told how his wife had supported him through ill-health as a result of a kidney transplant and was a loving and supportive mother to their son, Kori. She also volunteered with the local police, and, as a mark of respect, officers had lined up to salute her funeral procession.

In a victim impact statement read out to the court, Kori Morrison called for Gibbon to be locked up for the rest of his life. He said: “To me, I can’t fully understand how Trevor Gibbon would receive anything less than having to spend the rest of his life in prison.”