A new offence of stalking should be brought in immediately to stop harassment and intimidation turning to murder, an inquiry said on Tuesday.

But MPs and peers from all parties warned that a new law alone would not be enough to protect victims and "fundamental reform" of the system is needed.

The independent Parliamentary Inquiry into Stalking Law Reform called for key changes to be made to training, risk assessments and the treatment and sentencing of stalkers in the government's ongoing review of harassment legislation.

It comes after a man who stalked his ex-girlfriend on Facebook before stabbing her to death was found guilty of murder.

Clifford Mills, 49, attacked Lorna Smith after inviting her to his flat in Brixton, south London, in February last year. He denied murder, claiming that he was suffering a mental abnormality at the time, but an Old Bailey jury took just 90 minutes to find him guilty on Friday.

Another stalking victim, Claire Waxman, 35, was awarded £3,500 damages last week after the High Court ruled the state failed to protect her when charges against her stalker were dropped.

Waxman, who runs a business in Willesden Green, north west London, complained of "serious and persistent" harassment over eight years by freelance television producer Elliot Fogel, 36.

Lord Justice Moore-Bick said Waxman was entitled to damages in respect of the "alarm and distress caused by the failure of the CPS to pursue the prosecution".

"The state owed her a duty to take proper measures to protect her and was in breach of its duty in failing to pursue the prosecution," he said.

The inquiry recommended that anyone who breaches a restraining order should expect to be jailed and anyone charged with a serious violent or sexual offence should be refused bail unless there are exceptional circumstances.

Judges in crown courts should also have the power to suspend the parental responsibilities of anyone convicted of "serious" stalking-related offences in a bid to stop them making vexatious applications for contact in the family courts, it said.

The inquiry's 30 recommendations also called for a stalker's previous offences to be taken into account by judges and for restrictions to be placed on offenders' use of phones, IT and letters once they are behind bars.

A victims' advocacy scheme should also be set up to help support stalking victims through the criminal justice system, it said.

Elfyn Llwyd, the inquiry chairman, said: "Stalking is a crime which shatters lives - but for too long it has remained a hidden crime which victims have been reluctant to report, fearing that they wouldn't be taken seriously."

Current legislation was "clearly not doing enough to protect victims", he added, and a holistic approach by the Government was needed to tackle the problem early on.

Laura Richards, of Protection Against Stalking and an adviser to the inquiry, said: "It is time for change and to recognise the physical and psychological harm and terror that stalking causes.

"This is about murder prevention."

The inquiry heard how stalking victims have little confidence in the system, with most saying that police, prosecutors or the entire system let them down.

Campaigners said women were being "victimised at the hands of their stalker, and then again by the system".

Harry Fletcher, assistant general secretary of the probation union Napo, said the prison sentences being handed down to stalkers were so short that rehabilitation and treatment was impossible.

Just 20 stalkers a year are jailed for longer than 12 months for putting a victim in fear of violence, while some were behind bars for just days, and others were sentenced to community orders and "inappropriate" domestic violence courses, the inquiry heard.

Fletcher, an adviser to the inquiry, added that stalkers needed to be tackled as early as possible and, unless this happens, "behaviour escalates and can result in serious injury or even death".

Shadow home secretary Yvette Cooper has backed calls for change, blaming a "lack of clarity" in the law for allowing stalking cases to escalate into still more "heinous" crimes against both women and men.

"One of the things needed is a change in the law, to make sure the criminal justice system takes stalking more seriously and understands the scale of the threat and harm it causes," she said.

Some 120,000 victims, mostly women, are stalked each year, but just 53,000 are recorded as crimes by police and only one in 50 of these lead to an offender being jailed, the inquiry heard.

All the inquiry's members, including Tory MP Robert Buckland, Labour's Baroness Gibson and the Lib Dems' Baroness Brinton, backed the report's findings.

A Home Office spokesman said: "It is vital that victims of stalking get the support they need from the police and the courts and that offenders are properly punished.

"That's why we have been consulting the public on a specific offence of stalking and the need for better training and guidance for the police and Crown Prosecution Service.

"That consultation only closed yesterday and we need to carefully consider all responses before we act to ensure we get this right."