IT sounds an unlikely tale, but now it can be told - how an ancient Yorkshire ruin played a crucial role in the build-up to D-Day.

Nowadays Kirkham Priory, by the River Derwent in picturesque countryside near Malton, North Yorkshire couldn't be a more tranquil setting.

But in the first half of 1944, it was a hive of military activity as troops rehearsed for the storming of the beaches of Normandy.

The khaki-clad soldiers swarmed about the area and the nearby A64 resembled a massive car park for all types of Army hardware.

The banks of the river were used for large-scale trials of wading and amphibious vehicles destined for the beach landings.

And, in a top-secret visit, Winston Churchill and King George VI visited for a morale-boosting inspection of the troops.

The visit was clandestine and for years afterwards their was no proof that it had taken place at all.

However, following the publication of a magazine article which alluded to the area's war service, a photograph has been unearthed taken at the time.

A reader came forward with the yellowing image, showing Churchill talking to his grandfather, who was then a serving soldier.

English Heritage military historian Roger Thomas said: "The British 11th armoured division was amongst the units moved to Kirkham to give drivers experience of manoeuvring and to test waterproofing compounds. Vehicles ranged from tanks to jeeps.

"The visit to Kirkham by Churchill and the king shows that this was a key training area."

Even Kirkham's stone ruins were pressed into service, with troops tackling the walls using clambering nets, in fitting preparation for the rubble-strewn towns of northern France.

Now the episode has been commemorated, with the unveiling yesterday of a new plaque on the site, one of seven storyboards about the priory's history.

Kirkham Priory was built in 1121 by Augustinian monks and predates Fountains and Rievaulx Abbeys.

Custodian Linda Teal said: "New illustrations by Peter Dunn recreate the appearance of buildings like the refectory and infirmary.

"The very latest research has been used to provide visitors with a vivid window on the past."

English Heritage is engaged in a project to illustrate the 20th Century histories of its ancient sites, including Kirkham.

Among the findings, new light has been thrown on the use of Scarborough Castle in the so-called "boffins war" - when radio equipment capable of plotting incoming enemy planes or aiding lost allied pilots, was installed in the 12th Century fortress.