The Vale of Glamorgan Council is advocating a merger with Bridgend CBC ahead of a 28 November deadline for Welsh councils to suggest voluntary amalgamations.
Cllr Neil Moore, Labour leader of Vale of Glamorgan, will propose the merger at a council meeting on Monday on the basis the authority would otherwise be swallowed up by Cardiff City Council.
But this direction runs counter to the intentions of the Williams Commission, which instead urged The Vale of Glamorgan to align with neighbouring Cardiff and for Bridgend to coalesce with Neath Port Talbot and possibly Swansea CC.