Sir Peter Soulsby's controversial decision to develop two travellers' sites in Leicester has been challenged by a group of Labour city councillors.
Earlier this month, city mayor Sir Peter announced he would press on with plans for council-controlled pitches in Red Hill Way, Mowmacre Hill, and Greengate Lane, Beaumont Leys.
It followed months of consultation and ferocious opposition from campaigners.
Now, councillors from Sir Peter's party have used "call in" rules to try to get him to rethink the decision, which he had been set to personally sign off.
Under legislation, if five members question a decision made by the mayor, they can call it in and force it to be discussed by the council.
It is the first time the legislation has been used to question one of Sir Peter's decisions since he was elected in May 2010, and the first formal challenge from within the city Labour group.
The move has been made by councillors for Abbey Ward, Annette Byrne and Harshad Bhavsar, and Beaumont Leys members Paul Westley, Sundip Meghani and assistant mayor Vi Dempster.
Sir Peter said he was "comfortable" with the call-in.
He said: "On a decision as big and important as this I am not surprised. I really do understand that those councillors have to represent the views of the people in their ward. They have a job to do."
Sir Peter said he still believed he had made the right decision on the sites, but the issue will now have to be debated when the council meets on Thursday.
If the council recommends a different decision be taken, the mayor will announce a decision on that recommendation, with reasons, confirming whether he dismisses the alternative.
The Mercury attempted to contact all five councillors but only Paul Westley was available for comment.
He said: "I would like a rethink on the Beaumont Leys site. I accept the mayor has grasped the nettle on this, but people in my ward are unhappy, and I was elected to speak for them.
"Even mayors have to be accountable to the people and the council and they can be challenged. People don't elect us to be mice, shivering and whimpering."
Councillor Westley said he thought Sir Peter "should consider a site on Ratby Lane which is more suitable".
He added Sir Peter "may have to get used to more challenges, particularly when we look at the budget".
The LE4 Action Group collected 2,700 signatures on a petition against the sites in the north of the city, although about 2,000 of the names were discounted because they were of people living the other side of the city boundary, in places such as Birstall.
Group spokesman Roy Rollings said: "I am glad the councillors have called it in because it shines more light on the matter."
Opposition Liberal Democrat councillor Nigel Porter said: "It may be late but it looks like some Labour councillors have found the guts to stand up to the mayor."
Tory opposition councillor Ross Grant said he thought the call-in was a stunt.
He said: "It looks stage managed. It's a talking shop. It allows those councillors to claim they have opposed a decision people in their wards dislike."
