Police have a message for Sheffield United and Sheffield Wednesday fans ahead of the Steel City derby tonight - You can't wee in our helmets.
The South Yorkshire force issued the jokey message earlier this evening, along with a message for fans to stay safe.
They tweeted: "Families are divided, friendships are put on hold, banter is at a high. Let's have a good event, stay safe and NO you can't wee in my hat."
The message is an allusion to the theory that a pregnant woman can legally relieve herself anywhere she wants – even in a police officer's hat.