In a consultative report, the Commission said three out of four child killers were getting away with murder because rules of evidence and procedure made it difficult to convict if a child was killed while being cared for by two people. If it was believed that one of them was the killer, but there was no evidence to show which one it was, both are freed.
As a result, just over one in four (27 per cent) of these cases results in a conviction.
The Law Commission report emphasised that only the defendants could confirm the facts, as the victim could be either dead or too young to give evidence. Its recommendations would apply in cases where a child under the age of 16 had suffered 'non-accidental death or serious injury which must have been caused by at least one of a defined group of individuals' - one of whom must have had responsibility for the child's care at the time the offence was committed.
The Law Commission said the person responsible for the child should be under a statutory responsibility to assist the court 'by providing as much information as they can, regarding the circumstances in which the offence was committed'. A jury could draw adverse conclusions if they failed to co-operate.
Statistics published by Sussex police in 2000 showed that each week in the UK, three children under ten are killed or suffer injury - but in 61 per cent of cases no-one is prosecuted.
The Law Commission's proposals follow recommendations last year from the NSPCC's Full Stop campaign against child abuse.