A group of Girl Guide and Brownie leaders will not use a new promise which removes reference to God, and has received the backing of Bishop Nazir-Ali.
One atheist volunteer helper has accused the group of excluding her, and is being supported by the National Secular Society.
A spokeswoman from Girlguiding UK has signalled that groups which do not use the new pledge will be forced out of the movement unless they comply.
In June this year, Girlguiding UK changed their promise to replace “love my God” with a pledge to “be true to myself” following a consultation.
Critics said the move was “worryingly relativistic”, and now a group of leaders in Harrogate say they will not take on board the new pledge.
Hazel Mitford, Jayne Morrison and Alison Ellison voiced their “dismay” at the recent change, in a letter to their local newspaper.
It was co-signed by the minister of the church which provides premises for the guides groups.
The letter said: “The spiritual aspect is recognised in girlguiding and ‘God’ has been part of the promise since it was founded.”
“The divine is fundamental to everything it stands for. No-one need join girlguiding, so removing the reference to God in the interests of inclusivity removes much of what we stand for.”
“You would not join the Lawn Tennis Association and insist they had to make provision for all other sports.”
The Rt Revd Michael Nazir-Ali, the former Bishop of Rochester, said this group and others who wish to continue to use the original promise should be allowed to do so.
He said: “If these people really do believe in diversity and this is not just a back door to secular totalitarianism, they should be supported in this.”
But volunteer helper Jem Henderson, who describes herself on her blog as “post punk, feminist poet”, said the Harrogate leaders are forcing her to make a promise which excludes her as an atheist.
She said: “This demonstrates that the new promise is just for show, and that the Guiding movement, at least in Harrogate, is still excluding people from secular walks of life.”
Jem Henderson also said she joined the Guides as a volunteer because it had been described by the new chief executive Julie Bentley as “the ultimate feminist organisation”.
She added that some think the Girl Guiding movement is based on God but “actually it is based on girls”.
The National Secular Society has written to Girlguiding UK to ensure that all units will be required to use the new promise.
Mrs Mitford, one of the Harrogate leaders, said the issue is something that needed to be discussed “quietly and calmly”.