A GEORGIAN folly in the grounds of a North Yorkshire estate may be much more than it seemed when restoration work began.

The Landmark Trust took the unusual step of starting work on the refurbishment of The Ruin at Hackfall before it had all the £500,000 needed to cover the cost in its coffers.

There was real concern a rapidly deteriorating piece of history could be lost forever if work hadn't started immediately.

However, the risk appears to have been worthwhile as, while teams have been busy repairing the building, its similarity to work by famous architect Robert Adam became more and more apparent - and research now suggests the folly was probably built to one of his designs.

William Aislabie was the architect of the Hackfall gardens as well as the neighbouring water gardens at Fountains Abbey, near Ripon.

The new theory is that he saw Adam's watercolour, Capriccio on Ruins, based his folly on the building in the picture and then took Adam himself to the Hackfall estate to see the work in progress in 1758.

Robert Adam was born in Kirkaldy, Scotland, in 1728. He famously designed London's Portland Place, the facade of the Admiralty building in Whitehall and the Adelphi theatre, near the Strand.

Stephen Astley is the librarian at the Soane Museum, which is currently exhibiting examples of Adam's work - and he confirmed he is convinced by the discovery.

''Any new Adam attribution is big news,'' he said. ''The historical significance of The Ruin - as the folly was originally named - adds impetus to The Landmark Trust's appeal to raise the funds needed to finish the vital restoration work - £140,000 of an estimated £500,000 remains to be found.

Landmark Trust director, Peter Pearce, added: ''We are delighted by our discovery and we are helping to save such an important building.

''It is unusual for us to start on a project without first raising all the funds but we had to begin work at The Ruin as the building was collapsing. Unless more money is raised this crucial work will have to stop.''

Anyone who would like to contribute to the cost of the restoration of The Ruin can contact the Landmark Trust on (01628) 825920.