A violent drug-user who murdered his partner’s three-year-old son after inflicting more than 20 rib fractures during weeks of “horrendous” beatings has been jailed for life with a minimum term of 24 years.

Birmingham Crown Court heard that the force used by Nathanial Pope on Kemarni Watson Darby was similar to that normally caused by a car crash.

Convicted drug-dealer Pope, 32, was found guilty by a jury in April, following a five-month trial which heard that the little boy had 34 separate areas of external injuries.

Kemarni’s mother, Alicia Watson, was cleared of murder but found guilty of causing or allowing his death.

Watson, 31, was also convicted of child cruelty and was given an 11-year prison term at the same sentencing hearing as Pope on Tuesday.

Kemarni Watson court caseAlicia Watson and Nathaniel Pope were both sentenced on Tuesday (West Midlands Police/PA)

Jurors heard that the couple, who blamed each other from the witness box, continued to live together for several months after Kemarni died from abdominal injuries in June 2018 when his ribs were “crushed” at their two-bedroom flat in West Bromwich.

Pope was filmed by a police bodycam shortly after fatally assaulting Kermani – with footage showing him smiling as he denied any wrongdoing – and falsely claimed he was not Watson’s partner.

A video clip of the encounter with an officer was released by West Midlands Police after the sentencing, showing a shirtless Pope in an apparently relaxed mood despite what he had done.

Passing sentence, Mrs Justice Tipples said: “This is a particularly distressing and tragic case.

“Kemarni died on the afternoon of the 5th of June 2018. You, Nathaniel Pope, brutally assaulted Kemarni in the sitting room of his own home, and, knowing he was in extreme distress and pain, you left him to bleed to death.

“I am sure that you did this when Alicia Watson was out. When you (Watson) returned, you found Kemani’s lifeless body on the sofa and dialled 999.”

The judge added that Kemarni’s injuries had been the result of extremely severe force “compatible with the type of injuries seen in a road traffic collision or when an individual falls from a height”.

Watson knew Pope was injuring Kemarni with punches and kicks but had done nothing to stop it,  the judge said, while she also “regularly beat him hard” with her hands.

Kemarni Watson Darby deathCCTV footage captured toddler Kemarni Watson Darby returning with his mother to the flat where he was killed on June 5 2018 (West Midlands Police/PA)

Among the fatal injuries to the toddler’s body were four rib fractures believed by pathologists to have been caused up to four weeks before he was killed at his home in Beaconview Road.

Pope, who was jailed for four months in 2011 for a brutal attack on a young mother on a London bus, claimed he had not seen or heard the final fatal attack.

The former warehouse worker, from Wolverhampton, has previous convictions for burglary and possession of heroin with intent to supply.

Watson, of Handsworth, Birmingham, swore at Pope’s QC while giving evidence and denied any wrongdoing.

During the trial, it emerged that she had bought cannabis and spent money on driving lessons as Kemarni lost his nursery place due to lack of funds.

The trial was told that Kemarni would already have been in pain from serious injuries when, hours before he was beaten to death, he was taken by Watson to a walk-in health centre, where he was given medicine for a suspected stomach bug.