Why? Last month, a 15-year-old raped at a night club immediately reported to the police who could not provide a woman doctor. She went home and valuable evidence was nearly lost. Most victims, already weakened by trauma and physical injuries, are put off by such disrespect, variations of which are common.

After two years of domestic violence, which included rape at knifepoint, a woman complained to us: “They decided I was a mad black woman, so every time I called to report another incident you could hear in their voice, ‘Oh it’s her again’.” We took it to the Met’s Gold Group which reviews publicly sensitive cases. It was reinvestigated by another team. Then the Crown Prosecution Service (CPS) discontinued the prosecution, claiming the victim was unreliable.

Home Office research, A Gap or a Chasm? in 2005, describes a “culture of disbelief” among police, even among those specially trained in sexual offences, and stated: “The criminal justice system needs to shift from a focus on the discreditability of complainants to enhanced evidence gathering and case-building.”

In 1995 we helped two women to bring the first private prosecution for rape in England and Wales. Unlike most rape trials, the prosecutor believed his witnesses, and challenged attempts by the defence to discredit the victims, who had both been attacked while working as prostitutes. The rapist got 11 years on the evidence that the CPS had rejected. The CPS had presumed a prejudiced jury. Perhaps, at that time, it was the CPS that prejudiced.

Since, the present Director of Public Prosecutions, Ken Macdonald, has made it a priority to tackle the low rate of rape prosecutions and that is welcome. But we have experience of CPS carelessness and incompetence, of little interest in working for a conviction, of pointing to the victim’s weaknesses to dismiss rather than build her case, and of allowing the prejudicial tactics of the defence to go unchallenged.

Rape and domestic violence are often referred to as uniquely difficult to prosecute: one person’s word against another, no witnesses, sometimes no forensic science evidence. Yet racist attacks brought to us, where both assailant and injuries are obvious, suffer similarly. Only 7 per cent of recorded racially aggravated attacks reach conviction.

A Muslim mother claimed her broken nose and cheekbone were from a white male neighbour’s punches, in the presence of witnesses. The police visited the white accused, and only then spoke to her. They demanded names and birthdates of her children but, despite her obvious injuries, never asked her precisely what happened. Having handcuffed and searched her black partner, they left. As with Stephen Lawrence, they assumed that the victims were suspects.

Although her attacker had shouted “f*****g n****r”, police had not recorded a racially aggravated assault. They dismissed intimidation, saying that they cannot prove who bangs on her door after midnight — just what women who get silent calls from violent former partners are told.

This treatment of racist assault is again not uncommon. A black pensioner was informed by police that her assault by white people was “not a priority to investigate”. Two women a week are murdered by partners or former partners.

The police are diverting resources from sex offenders to terror suspects. More will now deal with “antisocial behaviour”. Defeating the terrorism of rape, domestic violence and racist assault needs no summary powers and no guns.

NEW POLICE POWERS