Ministers have pledged to introduce new laws to prevent parents who kill their children getting away with murder.

Home Office minister Paul Goggins said yesterday the Government was committed to closing a legal loophole, which allowed parents and guardians who killed to walk free from court.

He made the promise after MPs Des Turner and Tim Loughton highlighted in a parliamentary debate how two Sussex couples escaped murder charges despite young children in their care being brutally killed.

In 2000, a court heard evidence that a Brighton couple murdered two baby sons and a baby nephew.

All three tots were smothered. Medical experts also testified the father put his fingers down the babies' throats to stop them crying.

A year later, Simon and Michelle McWilliams, from Portslade, escaped prosecution for murder despite police finding 54 injuries on their four-year-old adopted son, John Smith.

All four adults were jailed for cruelty but murder charges were thrown out because there was no conclusive proof which parent was responsible for the deaths.

The killings prompted The Argus to launch a campaign and lobby two successive home secretaries.

Mr Goggins said: "We want to introduce legislation properly so killers are brought to justice and those who stand by and watch are also brought to book.

"I can't confirm when this will happen but I can confirm the Government will bring forward this legislation."

Mr Turner, MP for Kemp Town in Brighton, secured yesterday's prized adjournment debate, called The Law Commission Report On Child Deaths.

He wants ministers to follow Law Commission recommendations by beefing up sentences for cruelty and making both guardians culpable.

He also wants new offences of child cruelty contributing to death and failing to protect a child to carry maximum jail terms of 14 years and seven years respectively.

Police failed to press charges in 61 per cent of cases where a child died in suspicious circumstances, he said. Convictions for cruelty were secured in 27 per cent of cases.

Mr Turner said: "I can't imagine in the case of a murder of an adult either the police or the Crown Prosecution Service would let cases go unpunished or unprosecuted this easily."