Scarborough Council has revealed it has sacked a town hall official for leaking a confidential document to "an unauthorised third party."
It has given no more details about the leak.
The authority meets next week to discuss ways of improving security and ensuring that confidential documents that are meant to be seen only by certain councillors are not passed on to others.
The council's legal chief says it has become clear that documents have been occasionally leaked.
In November 2013 a further unauthorised disclosure of confidential legal information which could have jeopardised the council’s position in a commercial law case led to an immediate review of access to confidential reports.