hich may signal children are at risk from, or are involved with, serious violent crime. These may include: • increased absence from school • a change in friendships or relationships with older individuals or groups • a significant decline in performance • signs of self-harm or a significant change in wellbeing, or signs of assault or unexplained injuries • unexplained gifts or new possessions could also indicate that children have been approached by, or are involved with, individuals associated with criminal networks or gangs and may be at risk of criminal exploitation. The likelihood of involvement in serious violence may be increased by factors such as: • being male • having been frequently absent or permanently excluded from school • having experienced child maltreatment and having been involved in offending, such as theft or robbery. A fuller list of risk factors can be found in the Home Office’s Serious Violence Strategy. 161 Professionals should also be aware that violence can often peak in the hours just before or just after school, when pupils are travelling to and from school. These times can be particularly risky for young people involved in serious violence. Advice for schools and colleges is provided in the Home Office’s Criminal exploitation of children and vulnerable adults: county lines guidance. The Youth Endowment Fund (YEF) Toolkit sets out the evidence for what works in preventing young people from becoming involved in violence. Home Office funded Violence Reduction Units (VRU) operate in the 20 police force areas across England and Wales that have the highest volumes of serious violence, as measured by hospital admissions for injury with a sharp object. A list of these locations can be found here. As the strategic co-ordinators for local violence pre