Police officers have been put on restricted duties after an inquest jury ruled they were "more concerned with their own welfare" than a man who died after being Tasered by an officer.
Jordon Begley, 23, was shot with the 50,000 volt stun gun and hit with "distraction strikes" while being restrained and handcuffed by three armed officers from Greater Manchester Police (GMP). He died in hospital about two hours later.
While the initial Taser shock did not cause his heart to stop, the jury concluded that the use of the Taser and the restraint "more than materially contributed" to a "package" of stressful factors leading to Mr Begley's fatal cardiac arrest, the inquest at Manchester Civil Courts of Justice heard.
In damning conclusions, the jury also said the officer who pulled the trigger, Pc Terence Donnelly, inappropriately and unreasonably used the stun gun for longer than was necessary.
And after 10-stone Mr Begley, who offered "minimal resistance" was restrained, the armed police, among 11 officers called to the scene, were "more concerned with their own welfare than Jordon's", the jury said.
The jury heard Mr Begley was left face down, handcuffed behind his back, as the officers had a "Hamlet moment" to "gather themselves".
Tasers have never been ruled to have directly caused a death in a UK inquest involving police use of the stun gun.
But yesterday's verdict, following a five-week hearing, is believed to be the first time in the UK a jury has ruled that a Taser and restraint contributed to a fatality.
Mr Begley's family now intend to sue GMP after the incident at the family home in Gorton, Manchester.
GMP Assistant Chief Constable Dawn Copley, said the jury's conclusions had raised "a number of serious concerns".
Ms Copley added: "In considering the circumstances of Jordon's death, the jury has raised some troubling concerns.
"We will ensure that these are thoroughly examined and that every possible lesson is learned from this tragic case.
"In the interim, I have decided to restrict the operational duties of the officers involved in the Taser discharge and restraint until we have had time to fully consider the coroner's comments and have further dialogue with the Independent Police Complaints Commission."
Since the introduction of Tasers in 2003, Home Office figures show their use has increased by more than 200%, with one in 10 officers now armed with a Taser and more than 10,000 Taser incidents in England and Wales in 2013.
In a lengthy narrative conclusion, the jury ruled the discharge of the Taser and restraint were stressor factors that "more than materially contributed to the death of Jordon Begley".
The jury also concluded Pc Donnelly pulling the trigger for eight seconds was "not reasonable in the circumstances".
And he was also left too long, face down with his hands cuffed behind his back by the armed officers present.
Police had raced to his home after his mother called 999 during a row with neighbours at around 8pm on July 10, 2013.
Mr Begley was hit with the Taser, equipped with laser sights, from a distance of 70 centimetres (27 ins).
Mr Begley, a heavy drinker who also used cocaine and cannabis, grabbed a knife and was threatening to use it but had discarded it by the time police arrived.
But Mr Begley became agitated and told officers: "I don't give a f*** who you are, get out of my f****** house!"
Pc Donnelly opened fire with the Taser because he was worried Mr Begley might still have the knife on him and he took "one step too far" towards him despite orders to stand back.
As Mr Begley was hit, armed police units arrived and "burst" into the room, to restrain him.
Pc Dave Graham, Pc Christopher Mills and Pc Peter Fox all took part in the restraint and handcuffing.
Pc Mills applied two "distraction strikes" to Mr Begley's upper back using a clenched fist, which is standard police procedure as they cuffed him.
Shortly after, Mr Begley's breathing changed to "abnormal" and despite emergency first aid he was declared dead after being rushed to hospital by ambulance.
Outside court Mrs Begley, 47, described the jury's conclusions as "fantastic" and called for all police officers to wear body cameras.
She added: "After two years of fighting everybody, fighting the system, Jordon's day has come. That is all I ever wanted. The last two years have been hell.
"Those officers should not be patrolling the streets."
Mark McGhee, her solicitor, said: "The jury's decision is very far-reaching and raises issues that go well beyond the death of this individual."
But Ian Hanson, from the GMP Federation, representing rank and file officers said: "Whilst the jury's findings are noted and respected, we are not bound to agree with them.
"The Taser officer was approached by a man he reasonably - based on Dorothy Begley's own 999 call - suspected to be armed with a knife and violent.
"Unlike a jury, officers do not have five weeks to take decisions, and many of the criticisms do not appear to us to reflect the reality and duration of this incident."