The Campaign to Protect Rural England says it has until mid-May to mount a legal challenge against the development at Western Heights in Dover.

This comes after revised drawings submitted in February this year saw Dover District Council issue a notice granting full planning permission on April 1.

The plans, at Farthingloe, will see a thatched barn converted into a pub, as well as a stable into a retail shop.

A farmhouse will be converted into a bed and breakfast and Victoria Hall will become nine homes.

The Drop Redoubt will also become a new museum and visitor centre.

Outline planning permission has also been given to 521 homes, 90 retirement apartments, a health centre, 31 residential units and a 130 bed hotel and 150 person conference centre.

There will also be pedestrian access improvements as part of the works.

The plans have previously come under attack by CPRE and saw 570 residents signing a petition against them.

Brian Lloyd, CPRE Kent senior planner, said: “We continue to be extremely disappointed that Dover District Council has backed this major development in an Area of Outstanding Natural Beauty.

“This plan, if it goes ahead, will cause significant, irreversible harm to this beautiful and historic landscape...” - Brian Lloyd

“The site was never in the Dover Local Plan and it is an example of how major developments can get through.

“At the national level we will continue to lobby government to secure changes to planning policy to ensure that such development cannot happen in our protected landscapes.”

Mr Lloyd said: “We are seeking legal advice to see whether there are any grounds for us to mount a legal challenge and have until mid-May to decide.

“CPRE is also arguing for a community right of appeal so that when decisions are made the community can challenge them and stand up to developers who ignore their views.

“This plan, if it goes ahead, will cause significant, irreversible harm to this beautiful and historic landscape.”

The developer is China Gateway International and it is believed work will begin at the site in 2016.

Phil Eyden from Western Heights Preservation Society, said the society could not comment until more information has been given.

Mr Eyden did say he hoped the society would be part of the decision making process for where and how any financial investment to the site is spent.

He said: “We would also recognise that serious financial investment to protect the crumbling heritage may not be forthcoming from any other source so will be watching developments closely.

“We do fully support the idea of a visitors’ centre at the Heights as proposed in the plans.”