The tests would have cost thousands of pounds
Plans to ask councillors and staff at Shrewsbury & Atcham Borough Council to take a lie detector test have been vetoed by councillors.
The lie detector tests were to hunt out a mole who revealed planned job losses to the press and were originally approved by the council's standards committee.
If carried out, the test would have cost the council thousands of pounds.
But at a meeting on Monday night, councillors voted overwhelmingly to block the proposal at a full council meeting.
The plan had originally been approved by the council's standards committee.
The Conservative's deputy leader, David Roberts, said the idea had met with little sympathy.
"It is a serious matter without a doubt that we have a leak," he said.
"The whole idea that we go after the mole to find out who leaked information was a good idea but we lost the whole argument by coming out with the lie detector test. The mole has disappeared and dug himself into the ground."