A 'psycho' train passenger who knifed to death a man on a commuter train in front of his teenage son was today found guilty of his murder - his 30th criminal offence since joining a London gang in his teens, MailOnline can reveal today.

Darren Pencille, 36, stabbed 51-year-old Lee Pomeroy 18 times in a 'savage and unrelenting' onslaught on board a Guildford to London Waterloo train on January 4 this year.

This afternoon he was jailed for life at the Old Bailey and will serve a minimum of 28 years.

Pencille is a career criminal who bragged about his convictions for carrying guns and knives and battling rivals 'to the f***ing death' for his South London gang, MailOnline can reveal.

The cannabis-addict was a lieutenant in the South Man Syndicate [SMS] crew in the capital whose members have terrorised the areas of Tooting, Streatham and Thornton Heath since the 1990s.

Mr Pomeroy's widow Svetlana today told the Old Bailey that her husband's murder was a 'senseless loss of life', made worse because it was in front of their son who she said had lost his 'defender, guide and mentor'.

Pencille's extraordinary criminal past of 25 convictions for 30 offences - including slicing a man's neck in a row over a Rizla cigarette paper - was first revealed in a gang video posted on YouTube where he called on an enemy to meet and fight him.

One fellow gangmember who knew him well told MailOnline: 'He smoked weed constantly and was a complete psycho. I feel so sorry for the man he killed and his son'.

Today it can be reported for the first time he was seen by a psychiatrist 24 hours before murdering Mr Pommeroy but was certified as 'no risk to himself or others' - months after he told a hostel worker: 'I'm going to kill you you c***'.

Pencille was diagnosed with paranoid schizophrenia in 2003 but he refused to take medication - and instead treated himself by smoking super-strong cannabis each day.

The violent criminal past of Darren Pencille, 36, can be revealed by MailOnline today in an extraordinary gangland video (pictured in 2009) as he was found guilty of murder today

Darren Pencille, 36, is today guilty of murdering Lee Pomeroy on a Guildford to London train in front of his 14-year-old son

The pair argued on the train before the paranoid weed smoker called his girlfriend on the mobile in his left hand and said: 'I'm going to kill this man'. This is the moment he pulled the knife and stabbed his victim, which was caught on CCTV

This is the moment armed police arrested their man, who had been on the run with his girlfriend and claimed he stabbed his victim in self defence

Train killer Darren Pencille smokes cannabis on a YouTube video that reveals his long links to London gangs and convictions for violent crime, burglary and possession of knives and a gun

DOES CANNABIS INCREASE THE RISK OF PSYCHOSIS? Going from being an occasional marijuana user to indulging every day increases the risk of psychosis by up to 159 percent, research revealed in July 2017. Marijuana is thought to cause psychosis-like experiences by increasing a user's risk of depression, a study found. The two mental health conditions have previously been linked. Frequently abusing the substance also significantly reduces a user's ability to resist socially unacceptable behavior when provoked, the research adds. Study author Josiane Bourque from the University of Montreal, said: 'Our findings confirm that becoming a more regular marijuana user during adolescence is, indeed, associated with a risk of psychotic symptoms. '[Psychosis symptoms] may be infrequent and thus not problematic for the adolescent, when these experiences are reported continuously, year after year, then there's an increased risk of a first psychotic episode or another psychiatric condition.' The researchers, from the University of Montreal, analyzed around 4,000 13-year-olds from 31 high schools in the surrounding area. Every year for four years, the study's participants completed questionnaires about any substance abuse and psychotic experiences. Psychotic symptoms included perceptual aberration - for example feeling that something external is part of their body - and thinking they have been unjustly badly treated. The participants also completed cognitive tasks that allowed the researchers to assess their IQ, memory and stimuli response. Advertisement

Mr Pomeroy died on the eve of his 52nd birthday and was on his way to London for a day out with his 14-year-old son. A row broke out after Pencille jostled past the father and son in the aisle, sparking a war of words.

A row broke out after Pencille jostled past father and son. Knife-obsessed Pencille called his girlfriend and said: 'I'm going to kill this man' then pulled a blade from his pocket and knifed his victim 18 times including a fatal cut to his neck.

Pencille got off at Clandon, where he was picked up by girlfriend Chelsea Mitchell, 28, who ferried him away from the scene and helped him change his appearance. She was today found guilty of assisting an offender and sentenced to 28 months in prison.

Mr Pomeroy died a little over an hour later after suffering the fatal neck wound along with another eight to his torso and further cuts to his arm, hands and thigh in less than 30 seconds.

Darren Pencille calmly asked 'What's this about sir?' as armed police raided his girlfriend's flat less than 24 hours after he knifed to death a train passenger.

Pencille refused to give evidence at his Old Bailey trial claiming he had acted in self defence. But jurors heard how 5ft 10in tall Pencille had a history of violence, having previously stabbed a flatmate in the neck over a minor disagreement in 2010 and had threatened to kill a staff member at a mental health hostel in June last year.

A jury deliberated for 19 and a half hours to find Pencille, of no fixed abode, guilty of murder.

His girlfriend Mitchell, 28, of Farnham, Surrey, was found guilty by a majority of 11-1 of helping him evade police after the attack.

The court heard Pencille's criminal record contains 14 convictions for 19 offences which also include burglary matters, witness intimidation and possessing a firearm.

Mitchell has seven convictions for 10 offences spanning 2011 through to last year and mostly comprising threatening words and behaviour and assault.

Today's murder is his 30th offence.

British Transport Police (BTP) have released body-worn camera footage showing the moment armed police raided her flat in Farnham, Surrey, in the early hours of January 5.

Mitchell is seen opening the door before Pencille is ordered to back towards the entrance with his hands on his head before he is handcuffed by officers and taken into a waiting police van.

Pencille can be heard saying 'yes sir, yes sir' and 'please, I'm not going to do nothing, please' before asking: 'What's this about sir?'

The killer, who faces life behind bars today, revealed his criminal past online after he was accused by another gang in south London of being a rapist and a police 'snitch'.

Pencille's girlfriend Chelsea Mitchell drove him around the south of England after the murder and helped him change his appearance. She is guilty of assisting an offender at the the Old Bailey, where Lee Pomeroy's widow Svetlana attended the trial each day (right)

'He was our boy's defender, guide and mentor - a guiding light forever extinguished': Widow's heartbreaking tribute to passenger killed in front of his teenage son Lee Pomeroy on a Guildford to London train in front of his 14-year-old son The grieving family of Lee Pomeroy said they had lost their 'guide' in life. In a moving victim impact statement Mrs Pomeroy said her and her son's lives 'changed forever' the day her husband's life was 'cut short in such an unnecessary and cruel way'. 'Lee Pomeroy should have celebrated his 52nd birthday the day after he died,' she added. 'We had cards and presents for him which he never got to see. 'Life has become empty.' The court was told Mr Pomeroy, her husband of 18 years, 'doted on' their son and 'supported all of his hobbies and interests'. 'He was his defender, guide and mentor - a guiding light forever extinguished,' Mrs Pomeroy wrote. 'To compound the situation he was with his father when he died, and we have to eventually deal with that as well. 'I am in tears as this statement is being written because my heart is broken.' Advertisement

In response Pencille revealed his extraordinary list of criminal convictions and handwritten police statements to deny the allegations by proving he was never guilty of any sex offences.

MailOnline can reveal today Pencille had been charged with rape in his home town of Loughborough, Leicestershire, but the charge was later discontinued.

In the YouTube video, Pencille says to his rival who calls him a 'snitch': 'You're not in my league bruv - you're not on my radar. You ran, remember?'

When asked what he would say to anyone who believes he was a police informant he responds: 'Suck your mum. Why don't you come and confront me? I say that anyone', adding: 'SMS to the f***** death'.

As the train killer smokes cannabis in the background of the video, believed to be from ten years ago, a friend shows six pages of Crown Prosecution Service documents.

They reveal Pencille had been in prison and young offenders' institutions on at least three occasions between 1999 and 2004.

In 2004 he was convicted of possession of a gun and ammunition and jailed for just under three years.

Two years earlier he was twice caught carrying a knife on the streets of London, but was given a fine and community service.

Pencille also has one conviction for ABH, two for burglary, one of fraud, two thefts and driving without insurance.

The killer also was sent back to prison twice for failing to meet his bail conditions, MailOnline understands.

Pencille appears to have become an SMS member in his mid-teens and remained affiliated to the group, which had around 100 members at its peak, and known for attacking rivals Brixton, Peckham, Lambeth, and Streatham.

His girlfriend Chelsea Mitchell (left) was convicted of assisting an offender today after driving him from the scene and helping change his appearance including cutting his hair and giving him glasses (right)

Members as young as 12 have been linked to drugs offences and murders in London.

The train killer's extraordinary rap sheet and his 'fixation' with knives Pencille has a number of previous convictions and cautions for violence dating back to 1997. Pencille had been charged with rape in his home town of Loughborough, Leicestershire, but the charge was later discontinued. He was convicted of ABH following a fight in 1999 and twice convicted of having a blade, in 2002 and 2004. In 2010 he pleaded guilty to GBH with intent after stabbing a fellow hostel resident in West Norwood, south London, twice in the side of his neck, cutting his artery, and once in the shoulder following a 'minor disagreement' over Rizla papers. Pencille was jailed for four and a half years for that attack. In 2018 he admitted common assault after growing agitated at another housing facility in Brixton, screaming at a staff member that they were a 'c**t', adding: 'I'm going to kill you.' Pencille hammered on the staff room door with a fire extinguisher before traipsing away clutching a 'long metallic object' towards his bedroom where a kitchen knife was later found. Advertisement

In 2010 he pleaded guilty to GBH with intent after stabbing a fellow hostel resident in West Norwood, south London, twice in the side of his neck, cutting his artery, and once in the shoulder following a 'minor disagreement' over Rizla papers.

Pencille was jailed for four and a half years for that attack.

Last year he admitted common assault after growing agitated at another housing facility in Brixton, screaming at a staff member that they were a 'c**t', adding: 'I'm going to kill you.'

Pencille hammered on the staff room door with a fire extinguisher before traipsing away clutching a 'long metallic object' towards his bedroom where a kitchen knife was later found.

A consultant forensic psychiatrist who saw Pencille the day before the murder said he had been admitted to River House Medium Secure Unit in March 2015.

There he was observed to be 'confrontational and agitated' if he did not get his own way and 'angry and threatening' when his behaviour was challenged.

Pencille has been in contact with mental health services since 2003, has been diagnosed with paranoid schizophrenia and treated for psychotic symptoms.

But instead of taking his medication Pencille self-medicated with cannabis – which jurors heard would either calm him down or make him more argumentative.

Despite his violent tendencies and mental health problems he was deemed to have been 'no concerns of risk to himself or others' during his final appointment on January 3 - the day before the train murder.

His six-page list of convictions is waved at the camera and reveals he had a dozen convictions in five years

The most serious offence came in 2003 when he was jailed for 30 months for carrying a firearm and ammunition. He also had convictions for carrying knives

Killer smoked cannabis to treat his paranoid schizophrenia and was considered 'no risk to others' despite his threat to kill worker A consultant forensic psychiatrist who saw Pencille the day before the murder said he had been admitted to River House Medium Secure Unit in March 2015. There he was observed to be 'confrontational and agitated' if he did not get his own way and 'angry and threatening' when his behaviour was challenged. Pencille has been in contact with mental health services since 2003, has been diagnosed with paranoid schizophrenia and treated for psychotic symptoms. But instead of taking his medication Pencille self-medicated with cannabis – which jurors heard would either calm him down or make him more argumentative. There was deemed to have been 'no concerns of risk to himself or others' during his final appointment on January 3. Advertisement

Detective Chief Inspector Sam Blackburn said Pencille was 'very calm in his nature and reaction' and has never shown any remorse or taken any responsibility for what he has done.

'I think it shows that he is both devious and dangerous and he set out to kill Lee Pomeroy and he succeeded, unfortunately, in doing that,' he said.

'It's devastated not only Lee's mother, wife, sisters and obviously... the son. But that has had a devastating effect on them, (and) I hope they can start to rebuild their lives following this verdict.'

Mr Blackburn said Pencille had a history of violence and a string of previous convictions, including one in 2010 for stabbing a man in the neck during another minor row.

'He has a propensity for carrying knives and other weapons, and also, on his mobile phone, which we seized during the course of the investigation, we saw his fascination with knives and those knives recorded in imagery,' he said.

'He's a dangerous man. Quite clearly with his previous convictions, where he also stabbed another man in the neck, and his propensity for carrying knives, he showed his dangerous, aggressive nature and that he wasn't afraid to use that knife on that train on January 4.'

He added: 'His conviction in 2010 was almost like a mirror, apart from it not being on a train, where he did have an argument with another man and then stabbed him in exactly the same place - in the neck, causing a minor injury that time to the artery of the neck, not too dissimilar to our victim Lee.

'He was stabbed in the neck and unfortunately in his case, he sustained unsurvivable injuries.'

The disturbing images of multiple attack knives pictured by Pencille were shown to the Old Bailey jury

Jurors heard that when he was arrested over the fatal knife attack in January police seized and analysed his iPhone, which contained a series of knife pictures

Mitchell, 27, who denied assisting an offender, lived with her violent boyfriend in Farnham, Surrey.

Neighbours told MailOnline how the couple made their lives a 'living hell' - and feared for their own safety.

One couple said: 'They made 'anonymous' phone calls to my partners place of work claiming we are paedophiles.

Claiming we were making all kinds of noises day and night, which was simply all untrue.

'Neither worked and moved in around Christmas 2017 and the first few months were fine.

'Then around August 2018, their wild accusations about us, their loud music and repeated banging began.

'I've been off work due to anxiety caused by the situation. My fiancée has now been signed off from her work.

'We feel unable to move back to the flat because of what they put us through and now knowing what they have done, the thought of what could have happened to us is horrible'.

'What's this about sir?': Moment armed police arrested killer at his girlfriend's flat after he went on the run for 18 hours following train rage murder

Darren Pencille calmly asked 'What's this about sir?' as armed police raided his girlfriend's flat less than 24 hours after he knifed to death a train passenger.

The 36-year-old was described as 'devious and dangerous' by police as he was found guilty of murdering Lee Pomeroy the day before his 52nd birthday.

Pencille stabbed Mr Pomeroy 18 times in front of his 14-year-old son in a 27-second attack after a petty row aboard a London-bound train near Guildford in Surrey on January 4.

His girlfriend Chelsea Mitchell, 27, picked him up and bought hair clippers and razors for him to change his appearance as he sought to avoid capture. She was found guilty of assisting an offender.

This is the moment Darren Pencille was arrest - his response to police was: 'What's this about sir?'

Armed police hunted him down having gone on the run with his girlfriend for almost 24 hours

British Transport Police (BTP) have released body-worn camera footage showing the moment armed police raided her flat in Farnham, Surrey, in the early hours of January 5.

Mitchell is seen opening the door before Pencille is ordered to back towards the entrance with his hands on his head before he is handcuffed by officers and taken into a waiting police van.

Pencille can be heard saying 'yes sir, yes sir' and 'please, I'm not going to do nothing, please' before asking: 'What's this about sir?'

Detective Chief Inspector Sam Blackburn said he was 'very calm in his nature and reaction' and has never shown any remorse or taken any responsibility for what he has done.

'I think it shows that he is both devious and dangerous and he set out to kill Lee Pomeroy and he succeeded, unfortunately, in doing that,' he said.

'It's devastated not only Lee's mother, wife, sisters and obviously... the son. But that has had a devastating effect on them, (and) I hope they can start to rebuild their lives following this verdict.'

Mr Blackburn said Pencille had a history of violence and a string of previous convictions, including one in 2010 for stabbing a man in the neck during another minor row.