The lobbying group Christian Concern is preparing to take court action if the government presses ahead with legislation to ban conversion therapy.
The proposed law is likely to affect the counselling or prayers that churches and Christian groups can offer or provide to gay and lesbian people. It follows suggestions that people attracted to others of the same sex sometimes feel counselling or pressure from Christians amounts to a form of religious abuse.
Christian Concern says that if the government goes ahead with any of its proposals as part of the Queen's Speech on 10th May, it will bring legal proceedings.
Lawyer Roger Kiska is developing the arguments Christian Concern would to deploy in any court action.
"We're looking at a human rights challenge under the Human Rights Act - under the belief that the legislation at least as it now looks isn't compatible with the European Convention on Human Rights," he told Premier.
Despite Brexit, the Human Rights Convention is still a binding convention under UK law.
Christian Concern's lawyer says, so far, the drafting of possible legislation is problematic.
"This is going to be criminal law and they don't define any of the main terms. They don't define 'coercion' they don't define even what 'conversion therapy' is.
"How is a member of the public supposed to know how to guide their actions according to the law if they don't even know what the legal meaning is of these words."
Christians hold a range of view on conversion therapy, which remains a contentious issue within some church communities.
But Christian Concern believe that if the government includes legislation in the Queen's Speech it could be the first step in curtailing freedom of religion in the UK.
"Large parts of this law are really a straw man for something that could be much more nefarious - something that could really go to the heat of hurting religious freedom and the right of churches to do prayer ministry and things like that," Kiska told Premier.