Four police officers were assaulted in the north-east of England during one of the busiest nights of the year.
Cleveland Police dealt with 315 emergency calls on the Friday before Christmas, which is sometimes known as "Black Eye Friday" or "Mad Friday".
Ch Supt Emily Harrison said four officers had been spat at, elbowed and one was repeatedly punched in the face.
"They do not deserve to treated like this, they deserve the utmost respect when carrying out duties," she said.
A total of 31 people were arrested for a range of offences.