A VICTIM of domestic violence suffers more than 30 incidents of emotional or physical abuse before picking up the telephone to the police.
It is a shocking statistic, says Dolores Barrett, the Crown Prosecution Service's (CPS) top lawyer in Westminster, highlighting the importance of quick action in any reported cases of domestic violence.
It is an issue made more pressing by the likelihood of the perpetrator continuing to abuse, and the victim to refuse to press charges.
"There are complex issues that affect a complainant's decision to go ahead with a prosecution," she explains.
"One of the people in that relationship is in love, the other is in control. Usually the complainant has an emotional attachment to the perpetrator and they just want the violence to stop - not to have their partner sent to jail."
The longer a case drags on, the more likely a victim is to drop charges or even testify on behalf of the abusive partner if the CPS has enough evidence to press its own charges.
"Perpetrators of domestic violence tend to be very charming, manipulative people, who will lavish the victim with love and attention after an incident. They know that very few people will stay in a continuously abusive relationship, so they aren't always nasty. There's nearly a handbook to being a perpetrator of this kind of violence and it runs through patterns of abuse and control," adds Barrett.
Those factors have funnelled into traditionally low conviction rates across the country and added to the £2billion annual bill for taxpayers, covering costs of lengthy investigations and trials resulting in acquittals.
Only last month Refuge, the women's protection charity, said it plans to sue Manchester Police and the CPS for failing to protect Sabina Akhtar, 26, who was murdered by her husband in 2008.
It will be a test case, putting police and prosecutors in the firing line if violent partners are not prosecuted.
And it is one of the elements that has focused attention on the CPS.
In Westminster, under half of all reported cases where charges were brought led to successful convictions in 2006/7.
In the year leading to March 2009, the conviction rate had risen to 75 per cent, with the number of prosecutions brought nearly doubling to to 197, the third highest conviction rate in London.
So why the turnaround?
Domestic violence has moved up the legal agenda, together with an increased concern for women's rights (although around nine per cent of victims are men) across society.
"There's also been a cultural change at court," says Barrett.
"We will proceed with the case even when the complainant has withdrawn their initial statement."
Changes in law have helped too. The 2003 Criminal Justice Act empowered the CPS to use hearsay evidence in cases of public interest where there is a sole witness who may or may not be willing to go to court.
"We're also trying to influence the police to realise that domestic violence incidents are not suitable for a caution and should go to court."
Significant recent victories include the conviction of a man who repeatedly hit his wife in a Westminster street; an act denied by both the man and the woman, but witnessed by a passer-by, who called the police.
Westminster magistrates take domestic violence very seriously and with increasingly strong evidence being brought before court by the police - including background on a first time offender such as the number of 999 call-outs to their house - convictions are rising.
Prosecutors are now also savvy to the tricks perpetrators will deploy to string out a case and soften their partner in the hope of an acquittal.
In offences which can either be tried by magistrates or Crown court, violent partners will often choose to go before a jury in the knowledge that their wife or girlfriend is likely to withdraw charges as the incident escalates in seriousness.
"But we're getting very good at making the charges stick," says Barrett.
"The message to victims of domestic violence is to come forward and we help them and make sure their partner is no longer violent towards them or anyone else."
And to the perpetrators? "We are securing more convictions than ever. Violent partners can no longer carry on with impunity."
Refuge operates a 24-hour national domestic violence freephone hotline 0808 2000 247.