A Worcester judge has expressed "considerable concern" over a Malvern baby death case after the child's parents walked free from court.

Connor Prangley was found to have 17 rib fractures and a double fracture of his collarbone.

Born prematurely, he died on November 23 last year but pathologists could not confirm the cause of death.

The baby's mother Laura Prangley and her boyfriend John Hiles were charged with child cruelty "as a stop-gap measure" but the case ran into difficulties, prosecutor John Attwood told Worcester Crown Court.

In the face of ambiguous evidence, he alleged that either defendant could have caused the injuries and therefore the charge could not be proven.

Mr Attwood said the crown had considered bringing an alternative charge under section five of the Domestic Violence, Crime and Victims Act 2004 but to prove such a charge death had to result from "an unlawful act" by a defendant.

Two pathologists who carried out post mortems could not be sure of the cause of death.

Mr Attwood concluded that there was "no viable case" and subsequently offered no evidence against 24-year-old Prangley and Hiles, 35, both of Marlborough Gardens, Malvern.

They were given not guilty verdicts on the child cruelty charges and discharged.

But the judge questioned the framing of the Domestic Violence Act because it did not give scope for bringing a charge related to serious injuries.

He branded it "a peculiar law" and added: "Somebody caused these serious injuries. This case gives me considerable concern."

The judge asked the prosecution to pass on his concerns in the hope that the law might be changed.

The post mortem established rib injuries on both sides of the baby's body and also found was a brain injury, said Mr Attwood.

Home Office pathologist Dr Peter Acland and another pathologist concluded the brain injury was "probably non-accidental" but they could not be sure "beyond reasonable doubt".

There was a small chance that death was due to natural causes or it may have been accidental, the court heard.

Mr Attwood said if the case had come to trial the prosecution would have had to show that an unlawful act caused the death, which it could not do.

Michael Aspinall, for Hiles, said he maintained he did not cause the child any suffering.

Abigail Nixon, for Prangley, said she also denied any responsibility for the baby's injuries.

An inquest is yet to be held into Connor's tragic death. Care proceedings have begun in relation to Prangley's other child by another man.