In the United Kingdom, at least four young men were stabbed to death in unrelated incidents in London on New Year's Eve, while a fifth is in a critical condition in hospital. <br/><br/>Police today said the unusually concentrated spate of violence will add to growing concerns about knife crime in the British capital, which is at its highest level for five years. At least 80 people were killed in stabbings in London in 2017, more than half of them under the age of 25.<br/>'<br/>Mayor Sadiq Khan has launched a major campaign to reduce knife crime, including giving some high-risk schools metal detectors, while the government is also looking into tougher measures for<br/>people carrying knives.