'Knife crime' is simply any crime that involves a knife. Knife crime in London hits record high. What crimes are knives used for? % of knife crime by offence type, England and Wales, year ending March 2019. 7 days ago · Part-time special constables haven't been in such demand for decades. 'Knife crime' is simply any crime that involves a knife. “There were around 100 people at the event and someone who was there knows the identity of the person responsible,” police say.