The Woodland Trust says it is being gagged by the company behind the proposed new rail route linking Cambridge with Oxford.
The Trust say it has repeatedly asked East-West Railway for detailed maps of possible routes, but claims the company will only share them if they are kept confidential.
Click below for Wesley Smith's report
Woodland at Toft in Cambridgeshire lies close to a possible route for the proposed East-West rail line from Cambridge to Oxford.
As yet no detailed maps are being released of the five routes under consideration and that is causing concern for the Woodland Trust.
Jack Taylor, from the Woodland Trust, said: "We think they should be disclosing this information as part of the consultation, that way people can make an informed decision.
"We’re not against this project in principle if they can do it in the right way, then we have no qualms about it.
"However we have to ensure they’re fully considering ancient woodlands and protecting it.
"We can’t have habitats and our own sites like this affected by transport when there’s scope to avoid it.
"If we’re talking about ancient woodlands we’re talking about woods that have existed for centuries. We often compare them to being nature’s cathedrals"
East-West Railway point out there will be further public consultation based upon the best information they can provide at that time, but haven't given us any further detail on exactly why they aren't revealing detailed maps at this time.
The Woodland Trust claim signing a non-disclosure to get the information would be signing up to a gagging order, so for now, it's stalemate with more questions than answers.