Officials have been forced to shut the toilets at the council offices in King’s Lynn after “inappropriate behaviour” in them.
A key must be requested from the building’s reception if they are to be used.
A council statement read: “Inappropriate behaviour in the public toilets at the council offices has sadly meant that we need to keep the toilets locked with a key available at reception.
“This means the toilets are more likely to be used as intended and are therefore available for people who need them.”
The disabled toilet is operated using a RADAR key and remains unaffected.