The principal of an Anglican theological college has said that the government's proposed measures to tackle extremism could be a "disaster area" for people of all faiths.
Rev Dr Mike Ovey, who is principal of Oak Hill College in London, told the Telegraph that proposals for extremism disruption orders could have a "chilling effect" on Christian preachers and could even have an effect on theological teaching programmes.
The new extremism disruption orders, which are part of the counter-terrorism bill, are designed not just to target those who incite hatred but also those who are involved in "harmful activities" that pose a "threat to the functioning of democracy".
Shortly after the election David Cameron said: "For too long, we have been a passively tolerant society, saying to our citizens: as long as you obey the law, we will leave you alone.
"It's often meant we have stood neutral between different values. And that's helped foster a narrative of extremism and grievance."
Home Secretary Theresa May has also made numerous controversial statements about cracking down on extremism and tackling those who seek to "undermine our British values". While she has said that the definition of extremism will be made clear in the legislation, the idea of 'British values' is still rather loose.
The government's current definition of extremism is "vocal or active opposition to fundamental British values, including democracy, the rule of law, individual liberty and mutual respect and tolerance of different faiths and beliefs."
But May has said that an extremist could include those "spreading, inciting, promoting or justifying hatred on the grounds of disability, gender, race, religion, sexual orientation and/or transgender identity, proposing to overthrow democracy, members of the public, or a section of it, will be harmed".
Ovey, who is a former lawyer, warned about the legal implications of the proposals for people of all faiths and none.
"We don't know what British values are other than whatever Theresa May decides on the particular Monday when she wakes up and has to make one of these orders.
"Having an inclusive definition is hopeless from a legal point of view."
He suggested that under the current loose definition of British values, core Christian beliefs, including the belief that Jesus is the son of God, could be seen as offensive to other religions.
"Is a police officer going to listen to me saying that Jesus is the only way in a Muslim part of the East End?" Ovey said.
"There is always the argument that it will be OK on the night, yes you might be arrested but you will be released – but there is always the thought that you won't be."
He said that the "chilling effect" would make many people more cautious about what they said and did, and so there was a danger that those who continued to speak out could end up looking "extreme".
"The thing with a law like this is that there are going to be some people saying I'm not going to run the risk and someone like me who is going to run the risk is going to look more extreme.
"As a lawyer I think it is a disaster area and as a Christian believer and teacher I think it is a disaster area."
His interview with the Telegraph came as activists, including faith groups, atheists and free speech campaigners are preparing to launch a campaign against the government's proposals.
Last month the National Secular Society also said they thought the plans would have a chilling effect on free speech.
NSS executive director Keith Porteous Wood said: "The Government should have every tool possible to tackle extremism and terrorism, but there is a huge arsenal of laws already in place and a much better case needs to be made for introducing draconian measures such as Extremism Disruption Orders, which are almost unchallengeable and deprive individuals of their liberties."
Christian Concern has also opposed the proposed legislation, saying that they fear Christian groups could be labelled as "extremist" and citing a number of cases of discrimination against street preachers that they have supported.
Chief executive Andrea Williams wrote: "Theresa May will deny that her proposals are designed to silence people like us. But they do. They already have."