Birmingham's council leader has spoken of his concern that Solihull will refuse to sign up to create a West Midlands-wide combined authority.
Talks are taking place over the region’s authorities uniting under one banner, which could unlock a £20 billion pot if Labour take power next year.
Combined authorities have already been created in Greater Manchester, Greater Liverpool, and South Yorkshire, with the North East expected to follow suit.
However, while leaders in Birmingham and parts of the Black Country have signalled intent to work together, Solihull Metropolitan Borough Council looks set to offer the major opposition.
Birmingham City Council leader Sir Albert Bore said: “Solihull have made it quite clear that they don’t want to consider a combined authority.
“They are happy with the current arrangements, which are the Greater Birmingham and Solihull LEP (local enterprise partnership) arrangements.
“That puts me in a position where I don’t think that is the optimum economic geography for the sub-region.
“Leaving Solihull out of the Greater Birmingham and Black Country area would also be madness. Solihull needs to be part of it, just as the Black Country needs to be part of it.”
Sir Albert said talks were taking place about a new economic geography for the region, which may be badged Greater Birmingham, but the areas covered by the current Greater Birmingham and Black Country LEPs were “a good starting point”.
The leaders of councils in Sandwell and Wolverhampton have already expressed a desire to be a part of a wider authority.
Solihull Council leader Coun Ken Meeson said that a combined authority would destroy the “very successful” Greater Birmingham and Solihull Local Enterprise Partnership and create “an artificial combination of councils”.
He added: “Solihull does not believe that the proposal to effectively recreate the old West Midlands County Council is the right way to go. WMCC was always an artificial grouping in which individual councils struggled to maintain identity.
“The creation of a City Region under the previous government was also abandoned because of tensions between Birmingham and Coventry.”