A 69-year-old man found guilty of beheading his wife and flushing her head down the toilet has been jailed for life.
Dempsey Nibbs was informed by the senior judge at the Old Bailey that he would serve at least 21 years in prison.
The Recorder of London, Nicholas Hilliard QC, described the crime as an act of "grotesque savagery", telling Nibbs: "I'm sure you don't regret your wife's death save for its effect on your own comfort and well-being."
Nibbs had apparently become enraged after his 60-year-old wife Judith, who worked for Meals On Wheels, taunted him as their relationship began to break down, saying she had been seeing other men.
Nibbs, who has suffered from prostate cancer, told the court he had not meant to kill his wife and had only meant to "slap her around a bit".
But the jury disbelieved his story and found him guilty.
Nibbs' lawyer, Ian Henderson QC, said his client realised that poor health meant he would die in jail.
The attack happened on 10 April 2014 at the couple's flat in Hoxton, northeast London.
Nibbs initially hit the mother of his two children with an iron bar, knocking her out.
He then cut her head off, smashed it with a mallet, and disposed of the pieces down the toilet.
Next, the crane driver wrote a note to his 30-year-old son Kirk and called 999, telling police they would find two bodies at the property.
An officer broke down the door when he saw Mrs Nibbs' headless body through the letterbox.
He found Nibbs in the bathroom, brandishing a shotgun and a knife, attempting to stab himself.
Mrs Nibbs appeared to realise that her life was in danger, telling her sister and a colleague that her husband had grabbed her by the throat and threatened to kill her.
During a row about extramarital affairs three days before she died, she said she had had sex "eight times".
The following day, she left work with the words: "If I'm not in Friday, I might be dead."
In a statement, Mrs Nibbs' sister Frances described her as a "very kind and caring person", saying they were "shocked and devastated" by the murder.
"Whatever problems there were in her relationship, Judith did not deserve to die in such a callous and brutal way."