A young mother died in the street after her drunken boyfriend, who had a history of domestic violence, threw a mobile phone at her.
A court heard mother-of-two Levi Ogden "collapsed in a heap" after being hit in the neck by the phone thrown by Lloyd Birkby in Halifax town centre.
The 26-year-old suffered a cardiac arrest due to the impact of the phone causing bleeding in her brain.
After the argument, Birkby, 27, originally walked away before returning, kicking a passing taxi then launching a discarded phone at Ms Ogden.
Birkby has a history of domestic violence against the deceased and police had been called to their home 20 times.
Birkby has now been jailed for five years at Leeds Crown Court, Manchester Evening News reports.
The incident, which was caught on CCTV, happened following an argument between the pair during a night out in November last year, the judge was told.
Judge Geoffrey Marson QC told Birkby, of Langdale Street, Elland, West Yorkshire: "You will have to carry with you the knowledge that you have deprived the children of their mother.
"And it will no doubt affect them throughout the whole of their lives."
Birkby admitted manslaughter at a previous hearing.
He appeared for the 35-minute hearing via video-link from prison.
Although the judge was in court, both barristers appeared via Skype and journalists also followed the proceedings remotely.
The court was told Birkby had a history of domestic violence against Ms Ogden, serving a number of prison sentences for battery and with the police being called to their home around 20 times.
Dafydd Enoch QC, prosecuting, said the altercation on November 3 last year developed between the defendant and Ms Ogden, who was with her friend, Courtney Bland.
Mr Enoch said Birkby walked away but then returned in a “clearly angry frame of mind”.
After kicking a passing taxi, he picked up a phone which was lying on the ground.
Mr Enoch said Ms Ogden was about 6ft to 8ft away when Birkby threw the phone “with as much force as he could muster”.
He said Ms Ogden staggered for a few seconds and then “collapsed in a heap on the floor”.
The prosecutor said Birkby assaulted Ms Bland and continued to act aggressively towards two Street Angels, who came to help, and paramedics and police who arrived at the scene.
He said the force of the blow plus the violent twisting of Ms Ogden’s neck caused the bleeding in her brain.
Mr Enoch described the situation as a “tragic, violent incident”.
Stephen Wood, defending, told the court this was a “highly unusual” case.
He said it “could not have been reasonably foreseen” that Birkby’s actions would result in his partner’s death.
Mr Wood also told the court that his client has a mental age of 11 years and five months.
Birkby was given a sentence of two months in prison for assaulting Ms Bland to run concurrently with the five years for manslaughter.
Judge Marson told him: “It’s clear that you do pose a significant risk of harm to intimate future partners.”
Detective Inspector Natalie Dawson, of West Yorkshire Police, said: “This case is a tragic reminder to all of what can happen when excessive force is used to try and resolve a situation. Levi's death was completely unnecessary and demonstrates the perils of people resorting to violence.
“We welcome today’s sentence and hope it can bring Levi’s family some closure knowing the man who caused her death is now behind bars.”