A sickening trail of crimson footprints marked the final steps of special constable Nisha Patel-Nasri, who bled to death in her pyjamas after being stabbed in the groin outside her north London home at midnight on May 11th, 2006 – her third wedding anniversary.

Huge bloodstains at either end of the trail showed how she had staggered along the pavement after the initial thrust and then collapsed.

Weeping neighbours alerted by her screams desperately pressed towels on the spurting femoral artery while they waited for the ambulance. But she lost consciousness and died on the way to hospital, cradled in her hysterical husband’s arms…