Theo Usherwood explains: Boris Johnson's knife crime pledge

The pledge made today by the Conservative leader is to "come down hard on the scourge of knife crime" if the Tories return to Downing Street.

The promise includes arresting people carrying a knife immediately, charging them within 24 hours and cutting the time until people appear in court down to a week.

Boris Johnson also aims to "champion preventative work and stop violence from happening in the first place" by giving a £35m boost to the police's violence reduction units.

Following this he plans to put 20,000 more police officers on the UK streets this summer.