Urgent changes are needed to ensure parents suspected of killing their child don't get away with murder, childcare and legal experts said today.

They want to close a legal loophole under which parents accused of murdering their children can escape conviction if it cannot be proved which of them committed the killing.

If evidence fails to point to either parent or carer, both will go free.

An NSPCC report calls for a shake-up in the way child deaths are investigated and prosecuted, echoing a campaign launched by The Argus two years ago.

Research by Sussex Police found that of 366 investigations into children under ten who were unlawfully killed or seriously injured by their parents or carers, only 27 per cent of suspects were convicted.

The conviction rate for children murdered by strangers is 90 per cent.

Two years ago The Argus launched a campaign to shut the loophole following the acquittal of a Brighton couple who smothered three babies.

It has also campaigned with the family of four-year-old John Smith, who died at the hands of his guardians, Simon and Michelle McWilliam.

In 2000, The Argus was assured by then Home Secretary Jack Straw that a new law would be considered bringing stiffer jail sentences for guardians whose children die in their care.

The NSPCC working group, chaired by a judge, has produced a set of recommendations which could finally see his good intentions reach the statute books.

They include the effective end to the right to silence for adults responsible for a child at the time an injury occurred.

The report also wants a review of the sentencing powers of courts to ensure they adequately reflect the crime.

Detective Inspector Malcolm Bacon, who collated the figures for Sussex Police, said: "I have been a senior investigating officer on two major inquiries where it became obvious children had been killed by their parents or carers.

"On both occasions we were unable to secure a successful prosecution because it was not possible to identify which of them actually carried out the final fatal attack.

"If the judicial system fails, as the current system allows, these persons are literally getting away with murder."

The NSPCC has set up a Which Of You Did It? working group as part of its Full Stop Campaign.

It will present its recommendations to a conference at Cambridge University tomorrow.

Barbara Esam, an NSPCC lawyer, said: "We believe the implementation of our recommendations would make a real difference and would greatly improve the prospects of justice being done."