Late night revellers who urinate on the streets of Norwich city centre are warned they could face an £80 fine.
Drunken anti-social behaviour causes problems in city centres
The crackdown was in response to increased reports of clubbers using letterboxes as toilets, police said.
Officers will patrol the city centre streets, particularly the Prince of Wales Road area, and issue fixed penalty notices to any offenders.
A police spokesman said they had worked with the council to provide toilets and there was "no excuse" for the offence.
The road has a number of late night fast food shops and side streets have sheltered housing and retirement homes.
Inspector Gavin Tempest said: "We know in graphic detail just how horrible the effects of this have been for local residents and businesses.
"I really hope we can get the message out to pub and club goers that there is no need to cause offence but if they do, it may well cost them £80."