The number of "domestic" homicides in the capital has fallen from 47 in the year up to March 2004 to 23 in the past 11 months. Scotland Yard believes the drop is largely due to a new early-warning system that uses six factors or pointers that help their officers identify would-be "domestic" killers before they commit murder.
The new profile system, based on analyses of 35 domestic murders and around 420 related physical and sexual assaults, has been adopted by several other police forces and is expected to be used nationwide. Under the system, police called to a suspected violent incident involving a confrontation between a couple, or former couple, ask the victim six questions that help identify whether he or she is at risk of further assault or murder (see panel for details). If the victim, who in most cases is a woman, is considered a high risk then the suspected assailant is arrested, or the victim is given protection.
Domestic violence is the largest single cause of homicides, making up around a quarter of killings each year. Wife and girlfriend-beaters are also found to be responsible for many other crimes. The Met estimates that men who commit domestic violence are responsible for 24 per cent of all violent crime and half of offenders commit further crimes outside the home.
Nationally, two women in England and Wales are killed every week by a current or former partner. Every minute, police in the UK receive a domestic-assistance call, yet only 35 per cent of such incidents are reported to police. In London, around 100,000 cases are reported every year.
As part of the London scheme, the police are planning to set up a secure centre in Croydon, south London, for victims of domestic violence to offer support and take evidence. This is hoped to be the first of a network of "haven" centres for domestic violence.
Sir Ian Blair, the commissioner of the Metropolitan Police, said he expected that the profile system, known as Umbra, would be "rolled out across the country". He added that it was important to prosecute domestic violence offenders whenever possible even in cases where the victim has withdrawn their support and does not want to testify.
w Pregnancy: Violence increases if the victim is pregnant or has recently given birth. Research shows that 30 per cent of domestic violence starts or can intensify with pregnancy
w Stalking: Heightened risk is indicated if the suspect displays obsessive controlling behaviour, such as watching, following and frequent telephoning of partners or former partners
w Sexual assault: If the woman has been attacked sexually then the perpetrator is likely to commit an even more serious offence
w Increase in violence: A rise in the severity or frequency of assault indicates greater risk
w Custody: If the victim is involved in a dispute over contact with a child or is trying to end a relationship, she is more at risk
w Cultural restraint: If the victim is from a culture where contact with society and police is restricted, then any call for help must be given added weight