Investigations are taking place into Swansea Council and whether anything improper was agreed over spending arrangements to secure support from Conservative councillors for the Lib Dem/Independent administration.
Cllr Rene Kinzett, who has reported the matter, has resigned as leader of the five-strong Conservative Group.
In a statement he says:
"I resign as of tonight and I state the reason being that I seem to have lost the confidence of three of my Conservative group colleagues because I have taken a very strong line in the ethics involved in public spending, with the moralities of decision-making in an open and transparent manner, and safeguarding the interests of the taxpayers of Swansea."
The South Wales Evening Post adds:
He referred to the fact Liberal Democrat council leader Chris Holley and Independent John Hague had been referred to the local Government watchdog for Wales, along with Conservative councillor Paxton Hood-Williams, and that police had been called in by the ombudsman to consider whether a criminal investigation should ensue.
It is understood the matter relates to alleged discussions about support for the ruling Lib Dem-led coalition — and in particular, giving extra spending to projects in certain Conservative-held wards.
Council leader Chris Holley says that has not been wrong doing, he is pleased the police are investigating to "put matters to rest" and hopes for a "speedy result."