Nigel Farage's plan to rebrand the Brexit Party as the anti-lockdown Reform UK has hit a snag.
The Reform think tank has written to the Electoral Commission to complain about the proposed name change, arguing it could lead to "voter confusion".
The think tank, which argues for public service reform, has also written to Mr Farage asking him to reconsider.
The Brexit Party has applied to the Electoral Commission to formally change its name, with Mr Farage arguing that as well as keeping an eye on Boris Johnson's negotiations with the EU "further reform in many other areas" is needed.
Party chairman Richard Tice has said a new coronavirus strategy is needed "so that we learn to live with it, not hide in fear of it".
In its letter to Mr Farage, Reform said: "We are determinedly independent and strictly non-party political.
"As a charity, this independence is absolutely core to our reputation and work, and therefore the longstanding goodwill in our name."
It warned Mr Farage that "renaming the Brexit Party 'Reform UK' risks undermining that goodwill through the confusion and/or presumed association with a political party".
The think tank's director Charlotte Pickles said: "We are flattered that Mr Farage would want to copy our name, however in doing so he is undermining almost two decades of work establishing our reputation for producing genuinely reformist and evidence-based policy research.
"We are a small charity and our independent, non-party political status is absolutely central to our ability to raise funds to support our work.
"We are kindly asking Mr Farage and the Brexit Party to consider our very serious concerns and pick a different name."