Research company Tuned-In surveyed more than 350 16- to 24-year-olds and 30 per cent said they now think it is acceptable to carry a knife. A worrying 23 per cent said they would actually use one. More than one-third of the young people surveyed said a lack of police officers was the biggest reason for the increase in gun and knife crime. Douglas Dunn, managing director of Tuned-In, said: "Public confidence in the quantity...