Xavier Dore, 22, was given a life sentence by the trial judge - but told that he could be considered for parole after just 16 years in prison.
The case was referred to the Court of Appeal by the Attorney General, Jeremy Wright QC, and today three appeal judges unanimously agreed 16 years was “unduly lenient” and should be increased to 20 years.
Sir Brian Leveson, sitting with Mrs Justice Lang and Mr Justice Jay, said 16 years “failed adequately to reflect the aggravating features” of the case.
The judge said he was “very disturbed” that, after being involved in the killing, Dore had gone on to supply more class A drugs “notwithstanding the horror it must have generated”.
The judge also said he was “extremely concerned” about the message the sentence was sending out to the public as the case involved a very serious crime.
He said the “proper penalties” prescribed by Parliament “should bite”.
Dore was convicted at Leeds Crown Court in July of the murder of crane driver Colin Pierre, 31, who was shot with a sawn-off shotgun as a punishment over a drug debt.
Dore was also found guilty of two offences of kidnapping and false imprisonment, and offences of conspiring to supply class A drugs.
Mr Pierre, the father of a young daughter, bled to death after being wounded in the leg and left to die in woodland off Gledhow Valley Road, Gledhow, Leeds, on March 11 last year.
Zoe Johnson QC, for the Attorney General, said Dore, from Chapeltown, Leeds, had been described as “one of the minions” of Anthony Micah Pyke, the drug dealer who pulled the trigger.
But he had been “a willing part of Pyke’s team” and the 16-year minimum sentence “failed to reflect the gravity of this horrific killing”.
Pyke, 33, was given a 32-year minimum prison sentence after being found guilty of murder and two offences of kidnap.
Dore was a criminal associate of Pyke’s and was involved in dealing heroin and cocaine.
He took part in kidnapping Mr Pierre and another man after they had smoked drugs which they had not paid for. Dore also helped drive the two men to the woods.
The other man was forced to kneel. Mr Pierre was shot in front of him and fell down a bank and bled to death. His body was later found in a stream by a schoolboy.
The increased sentence was welcomed by the Attorney General, who said: “Xavier Dore assisted in what was clearly a punishment killing, committed with the use of a sawn off shotgun.
“The victim was shot in the leg and was left bleeding to death in a public place.
“I asked the Court of Appeal to look again at this sentence as I felt that the minimum term of 16 years’ imprisonment failed to reflect the seriousness of Xavier Dore’s involvement in this crime.
“I wish to extend my sympathies to the family of Mr Pierre; he was a father, son and brother and I hope this increased sentence offers them a measure of comfort.”