Retired police chief Jim Marshall has called for change in the law after two cases involving the deaths of children.

He is backing our campaign to crack down on child killers, launched after a Brighton couple were acquitted of murdering three babies.

The judge ruled there was insufficient evidence to say which parent was responsible.

In another case, the adoptive parents of John Smith were jailed for eight years for cruelty after the youngster died with 54 bruises on his body.

His adoptive parents, Simon and Michelle McWilliam, were charged with murder but this was dropped because each blamed the other for inflicting the fatal blows.

Mr Marshall, former head of Sussex CID, said: "I have been saddened and shocked by the suffering of these children.

"The law needs to be changed urgently to eradicate injustice and to protect defenceless children."

Mr Marshall has written to Home Secretary David Blunkett saying: "It seems there is a licence to kill with impunity."

Two years ago The Argus was assured by then Home Secretary Jack Straw that a new law with stiffer jail sentences would be considered.

Police research showed although there were several hundred cases a year where children were killed or injured, two thirds of charges were dropped before going to court.

Mr Marshall, of Goldstone Crescent, Hove, said: "It is a major legal loophole. The prosecution can't prove who struck the fatal blow."

A Home Office spokesman said as the law stood, couples had been acquitted of murdering children where there was no evidence as to which person was responsible.

The spokesman said: "The only sure way of avoiding double acquittal for lack of evidence would be for the co-defendants to be presumed guilty unless one or the other proved his or her innocence."

The McWilliams have been granted leave by the Court of Appeal for a hearing to have their sentences cut.