Terry Fletcher visits a remarkable collection of historic artefacts in Helmsley. Photographs by Joan Russell

If Lego ever decided to add life-size mediaeval abbeys and castles to its range, the result might look a bit like the inside of a very unusual warehouse on the edge of the North York Moors. Here, neatly stacked and catalogued on reinforced shelving, you’ll find gargoyles galore staring at you from alongside exquisitely-preserved stone carvings and decorated floor tiles that were walked on by princes and bishops.

The historic treasures belong to English Heritage and have been rescued over decades from more than 100 historic sites in its care all over the north of England from the Scottish border down to Lincolnshire. Although it may look like the ultimate spares department or even a particularly specialised branch of B&Q, it is officially English Heritage’s Reserve Collection, made up of millions of pieces that will not fit into the various museums dotted around the charity’s sites, such as Rievaulx Abbey and Middleham Castle.

It traces its beginnings back to the 1930s when the then Ministry of Works took over ancient monuments with the remit to preserve them for the nation and prepare them for visitors. Many had been quietly mouldering for centuries, plundered for building stone and now swathed in ivy and buried beneath the rubble of their own collapsing walls or filled by the accumulated detritus of the centuries.

Susan Harrison, curator of the collection, says: ‘The aim then was to protect the sites and to make them safe for visitors. That was the start of the classic English Heritage look of clipped lawns. It was a huge job. Some had several metres of overburden, which had to be cleared to get down to the original levels.

‘There was so much spoil to be moved that light railways, like those used in mines, were built to help to clear it all away and within all that spoil they found many important pieces. Some of it could be put on display on site if there was a suitable roofed building but it was usually a tiny proportion. There was just far too much of it, far more than any museum could display sensibly and even if they could have shown it all, visitors would be completely overwhelmed by the sheer amount of material.’

And so millions of pieces ranging from stone carvings and tiles to metal work, not to mention paper archives of the digs which have taken place at many sites, are stored in the chilly warehouse on the outskirts of Helmsley.

But, despite appearances, the collection is not there to provide spare parts. Instead it is a resource for academics studying every aspect of life in the great castles and abbeys and the way they were built. Stones from arches can be used to extrapolate the span of the original structure and the quality of tiles can reveal a lot about the layout and use of the buildings.

Scholarly calls for help come in every week and at the same time Susan conducts her own research among the items in her care. She says: ‘I did a history of art degree and always wanted to work in museums. I came here on an eight week contract and I’m still here 20 years later so I’m just about getting to grips with it. It’s a brilliant job doing the detective work and putting two and two together to discover something we did not know before.’

Often those discoveries are mainly of interest to specialist historians and archaeologists but every now and again one hits the headlines, as in 2010 when she discovered an 1,800-year-old bust of the Roman god, Jupiter, in the store. It had been brought to England from Italy some 400 years ago to form part of a collection belonging to the Earl of Arundel and subsequently found its way to Studley Royal, part of what is now the National Trust’s Fountains Abbey estate near Ripon. Then it vanished, apparently lost for ever, until Susan identified the metre-high marble figure in the store. ‘That was very special,’ she said.

Kevin Booth, English Heritage’s senior curator for the north, says that although few members of the public actually see the collection, they still benefit from it. ‘Most museums have a reserve out of sight which may be as much as 95 per cent of what they have. But the research done here and the knowledge we gain underpins the work we do at our sites. It constantly feeds into things like interpretation boards and the information panels in the museums so the wider public does get the benefit.’

But it is not just the secrets of the artefacts themselves that are revealed. The collection can also tell much about the men who created them and their beliefs. Susan points to a carving of a cluster of leaves finished in minute detail. It would have formed a keystone high in the vaulted ceiling of an abbey church. ‘It would have been far too high for any human eye to appreciate it,’ she says. ‘But that was not the point. It was still carved in perfect detail because although men would not see it, God would. That was the depth of their belief. It tells us so much’ w

The collection is open to the public during free monthly guided tours from April to October. They are held on Fridays and can be booked through Helmsley Castle on 01439 770442.