Aaron Wilks, 38, unemployed, of Ash Grove, Bognor Regis, was sentenced at Portsmouth Crown Court on Thursday 16 December, having been found guilty by a unanimous jury on 10 December.
He will serve a minimum term of 25 years and was also given, to be served concurrently with the life sentence, six years for blackmail, 30 months for possessing an offensive weapon, 21 months for criminal damage and 20 months for arson.
Mark Stoakes, 60, had been at home with his family on the evening of Thursday 8 April, 2021 when they noticed their garden gate was on fire.
Mark and his wife ran to the front of their house in Oak Grove to see who was responsible for starting the fire. There, they encountered Aaron Wilks.
Wilks was holding a blue bottle and began spraying a liquid towards the victim and his wife. Mark, protecting his wife, stood nearest Wilks and became drenched in liquid - a liquid later confirmed to be petrol.
Wilks then produced a flame, which ignited a fire instantly. Mark suffered extensive burns and was taken to Chelsea and Westminster Hospital in an induced coma. Sadly, he died from his injuries three weeks later on Friday 30 April.
Senior Investigating Officer Detective Inspector Pauline Lane has said: "This was a horrendous and deeply distressing incident that has resulted in the tragic loss of a beloved husband, father and friend.
"Aaron Wilks attended the victim's home address on the evening of April 8 armed with an accelerant and a lighter, intent on causing harm.
"The subsequent assault was the culmination of a campaign of threatening and aggressive behaviour by Wilks towards Mark Stoakes over an apparent unpaid loan.
"We're grateful to Mark's family for their bravery and dignity throughout, and to witnesses and the wider community for supporting our investigation."
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