A national heritage charity is taking Guildford Borough Council to the High Court in a row over controversial plans for the fire-ravaged stately home at Clandon Park.

The Georgian Group says the council acted unlawfully when it approved proposals to keep the Grade I listed mansion largely as a preserved ruin rather than fully restoring its lavish 18th-century interiors.

The group has launched a judicial review: a legal challenge over how the decision was made, not just what was decided.

At the heart of the dispute is Clandon Park, one of the most important early Georgian houses in England.

Designed in the 1730s by Venetian architect Giacomo Leoni, it was famous for its grand marble hall, ornate plasterwork and richly decorated rooms. Most of these gorgeous features were destroyed in a devastating fire in 2015.

The National Trust, which owns the property, now wants to stabilise what is left of the building and open it up as a dramatic, fire-damaged shell with walkways and viewing platforms, rather than reconstructing the lost interiors.

Guildford councillors backed those plans unanimously in March 2025.

But the Georgian Group, a charity set up to protect buildings from the Georgian period, argues that approach could weaken protection for historic buildings across the country.

Its director, Dr Anya Lucas, said the case goes far beyond one Surrey mansion. She warned that if councils are allowed to reassess a building’s importance based on its condition after a disaster like a fire, it could set a “dangerous precedent” for other listed buildings.

In simple terms, the group fears that once a historic building is damaged, decision-makers might start treating what is left as less valuable, making it easier to approve big changes.

The charity stresses it is not taking legal action against the National Trust. Instead, it is challenging the council’s decision-making process, arguing heritage laws and policies were not properly applied. The Trust is involved in the case as an “interested party” because it submitted the plans.

A judicial review will not re-run the planning debate. Instead, a judge will decide whether the council followed the law correctly when granting planning permission and listed building consent in 2025. The High Court must first decide whether to allow the case to go ahead.

The National Trust says it still believes its scheme is the right way forward. A spokesperson said the project would conserve the surviving structure and make Clandon “a welcoming, fully functional building for current and future generations.”

A Guildford Borough Council spokesperson said: ‘We will respond to argue our decision is lawful. It will then be for the High Court to decide whether to allow the appeal to proceed to a judicial review hearing.”