The man who helped convict notorious double-killer Michael Stone has been jailed for life for his part in the murder of a drug dealer.

Eight years ago Stone was found guilty of killing Lin and Megan Russell in Chillenden – after Damian Daley gave evidence for the prosecution.

Daley told the court that Stone had confessed to him in prison that he had carried out the dreadful attacks on the 40-year-old mother and her six year old daughter in 1996.

The jury was not told of the Stone case after Judge Adele Williams placed a ban on the press mentioning the link between the two.

But last month, the jury convicted Daley of helping in the murder of drug dealer Gus Allman in Folkstone.

They also found Timothy Avril guilty of stabbing Mr Allman seven times and found two others guilty of perverting the course of justice.

Two others had already admitted their part in the incident and all six were sentenced today.

Both Daley and Avril were sentenced to life imprisonment with a minimum term of 20 years before they are eligible for parole.

Mr Allman's family packed into the court room, and there was an audible gasp when Judge Adele Williams handed down the sentence.

Describing the case as one of wilful murder of Mr Allman, Judge Williams said: "This was all to do with some drug turf war or argument.

"Mr Allman picked up a bottle as he went in the flat in Folkestone but I am sure both of you were waiting with knives when he entered the premises and he was stabbed seven times."

Judge Williams told Avril he had set himself up in the flat to supply drugs in Folkestone and turning to Daley, whom she described as a violent and manipulative man, Judge Williams said: "You armed yourself and joined in the attack on Mr Allman, even to the extent of following him out into the street.

"This was a drug-related argument during which each of you used a knife. This was a brutal murder."

Judge Williams said she had read the victim impact statement from Mr Allman’s mother which she said made moving reading.

"Hers and her family's sense of loss is very great indeed," Judge Williams said. "Mr Allman was talented, well loved and loving. No sentence I can impose will compensate for his loss."

As he was led away Daley started shouting.

Judge Williams said Alford and Marshall had behaved in an irresponsible fashion and their lies over what had happened delayed the police investigation by 22 hours, during which time significant forensic evidence was lost.

She described Williams as a weak young man and Smith as a heroin addict who had washed the blood from the walls and floors of the Folkestone flat and from Avril’s trainers in an effort to help the murderers.

Meanwhile, co-defendant Dean Alford, 20, of Wadden Hall, Canterbury, was handed three years after pleading guilty to perverting the course of justice.

Melech Marshall, 19, of New Cross in London, received three years for perverting the course of justice. He was handed a further three years to run consecutively after admitting three charges of possessing class A drugs with intent to supply at an earlier court hearing in London.

Laura Smith, 27, of Harvey Street in Folkestone, denied perverting the course of justice, but was convicted and today received a sentence of four years.

Michael Williams, 20, of East Dulwich, also denied perverting the course of justice but was found guilty and sentenced to three years in prison.

Last month the jury heard details of how a bust-up over drugs led to a 20-year-old Mr Allman being stabbed inside a Folkestone flat.

A doctor was flown by helicopter to close to the M20 to join the battle to try and save his life but he died from his injuries.

Drug-dealer Avril, 22, and pal Daley, 39, had denied murder. Avril admitted stabbing Mr Allman but claimed it was in self-defence and Daley said he was in an upstairs room and took no part in the killing.

Prosecutor James Mulholland QC revealed how Mr Allman had arrived from London in an Audi at a flat in 20, London Street in Folkestone shortly before 7pm on February 19.

"He died two hours later at the William Harvey Hospital in Ashford," he said. "He was 20 years of age. He had been stabbed seven times inside the flat.

A doctor was flown by helicopter to close to the M20 to join the battle to try and save his llife but he died from his injuries.

Mr Mulholland said that Avril "was by his own admission a drug-dealer" and police later found wraps of cocaine at the Dulwich home he shared with his mother.

He told how Avril travelled frequently from London to Folkestone to supply drug addicts and used the flat in London Street as a base.

"He rented Flat 2 from Laura Smith and used it as a base for his drug dealing activities. Laura Smith lived there with her boyfriend, Damian Daley," he added.

After the sentencing, Detective Inspector Lee Whitehead said: "On February 19 2014, Mr Allman travelled from London to Folkestone along with Marshall, Alford and Williams.

"A quantity of heroin changed hands at a house in London Street - where Mr Allman was stabbed by Daley and Avril.

"It was at this point that the group’s efforts to hamper any subsequent investigation began.

"Mr Allman’s associates drove him to Wood Avenue before calling for medical assistance. They later denied having travelled down to Folkestone with Mr Allman at all, instead insisting they had come across him by coincidence.

"Meanwhile, Smith had tried to clean up the house in London Street to hide any signs of an attack. Carpets had been cut up and walls, doors and clothes washed in a failed attempt to remove any traces of blood.

"I'm pleased to see Mr Allman’s violent killers jailed for a suitable length of time – and I’m also pleased that the courts have seen fit to jail those who tried to help them evade justice."