UK Oil and Gas had its access rights to Markwells Wood rescinded last year, according to protest groups.
Campaigners have accused the oil company of failing to publicise a decision by the landowner last year that they claim revised the access arrangements for the controversial site.
A planning application for exploratory drilling at Markwells had been withdrawn at the time after concerns about potential risks to the water source underneath the well.
Asked to confirm or deny the access issues, a UKOG spokesman said the company had no other comment than: “We will discuss and agree the access once the groundwater issue has been resolved.”
Speaking for Markwells Wood Watch, campaigner Julian Neal said: “UKOG has had no access to its Markwells Wood site since July 2017.
“This followed a decision by the owners of the land through which UKOG gained access to its site to terminate the legal agreement that enabled UKOG to pass through this land.”
Last month, UKOG applied for a High Court injunction prohibiting protest actions such as trespass, slow-walking and lock-ons at its West Sussex sites.
The latest draft of the injunction has yet to be presented in court.
Green MEP Keith Taylor said that not having access rights to the site ‘didn’t look good’ for UKOG.
He said: “Not only does it appear that the firm failed to communicate the South Downs National Park Authority decision to turf it out of Markwells Wood to their investors, it seems the firm has been sitting on the news that it hasn’t had any legal right of access to the site for the best part of a year.
“It makes quite the mockery of UKOG’s draconian and anti-democratic injunction application that seeks to keep protestors away from a site to which the company has no legal right and no reason to be on.”
The High Court has yet to decide the injunction case.