One local Age Concern has said it is yet to be convinced of the benefits of the merger between Age Concern and Help the Aged, and a second has accused the new national body of being more concerned about colour schemes and font sizes than clarifying its basic aims and purposes.
The charities united six months ago under the legal name Age UK in the biggest voluntary sector merger for seven years.
But Age Concern Birmingham, one of the largest individual Age Concern charities, has yet to decide whether to join the new federal structure or continue operating alone under the Age Concern name.
"There is no real evidence so far of any benefit to older people or to local Age Concerns," said Iain Mackintosh, head of development at Age Concern Birmingham. He said his trustees would decide whether to join Age UK only when it was clear what it stood for.
"Our responsibility is to older people in Birmingham, our staff and volunteers, and we won't agree to anything that undermines our local autonomy," he said.
Another senior figure at a local Age Concern, who did not wish to be named, said Age UK was "in serious danger of losing the goodwill of Age Concerns through its inability to clearly state what it is trying to do and how it intends to work with them".
He said it wasn't clear whether Age UK, which has shed 300 jobs since April, was more interested in selling products or becoming "a charity dedicated to helping vulnerable older people. Age UK seems to be worrying more about Pantone colours and font size than about its basic aims and purpose."
By contrast, Dil Daly, chief executive of Age Concern Liverpool, said local groups had been consulted throughout and it looked forward to the launch of the new brand.
A spokesman for Age UK, which said it paid brand consultancy Corporate Edge less than £100,000 for rebranding, said there was a two-year transition agreement in place between the new charity and existing Age Concerns, and that extensive consultations had taken place.
"The new charity fully recognises the rights and responsibilities of local Age Concerns as independent charities," he said.