LONDON — Fried chicken, a mainstay of takeout food in Britain, normally comes in colorful paper boxes with a company logo or a joking reference to the succulent contents inside.

But this week, customers at chicken shops across the country will instead encounter boxes with a government message about knife crime, which has been rising in Britain in the past four years and has become a political issue.

The boxes are all black with the hashtag “#knifefree” printed on the lid, a reference to a government campaign against knife crime. Inside are firsthand accounts from reformed knife offenders. The government hopes the messages will help reduce the numbers of young people carrying knives.

“These chicken boxes will bring home to thousands of young people the tragic consequences of carrying a knife and challenge the idea that it makes you safer,” Kit Malthouse, the policing minister, said in a statement on Wednesday.