A couple in the UK who murdered their baby son after he was placed back into their care, have been sentenced to life imprisonment, a media report said on Saturday.

During the sentencing on Friday, Judge Amanda Tipples said Stephen Boden and partner Shannon Marsden from Chesterfield, Derbyshire, had subjected their 10-month-old son Finley to "unimaginable cruelty", the BBC reported.

The court heard the murder was "savage and prolonged" with a "sadistic motivation".

In the early house of December 25, 2022, paramedics were called to the couple's "cluttered" and filthy terraced home in Holland Road, Old Whittington, after Finley suffered a cardiac arrest.

He was taken to hospital and later pronounced dead.

Finley's injuries included 57 breaks to his bones, 71 bruises and two burns on his left hand -- one "from a hot, flat surface", the other probably "from a cigarette lighter flame".

The court heard the fractures to Finley's bones led to him developing infections, including pneumonia and sepsis that ultimately killed him.

Toxicology tests showed cannabis was found in Finley's blood, indicating that he must have inhaled smoke in the 24 hours before his death, reports the BBC.

The court heard Boden, 30, and Marsden, 22, who were convicted of murder following a trial, worked together to keep professionals away from Finley to protect each other and cover up serious violence.

This included cancelling a health visitor appointment two days before he died and telling social services when they arrived unannounced that Finley may have Covid-19 and refusing to let them in.

The judge said they were "both persuasive and accomplished liars" who denied Finley medical care that would have saved his life.

"No-one heard Finley cry or scream in pain because you inflicted the injuries on him together, with one of you fracturing his bones and the other keeping him quiet with your hand over his mouth."

After Finley was born on February 15, 2020, social workers had decided to remove him from his parents as the local authority, Derbyshire County Council, believed he was likely to suffer "significant harm" at home.

Over the next six months, Boden and Marsden lied to social workers to persuade them they had made positive changes, helped by Covid restrictions that limited physical interactions.

Finley was returned to their care after a family court hearing on October 1, the papers of which were released after a media application to the High Court.  (PB/NewsGram)