The three massive earth henges at Thornborough in North Yorkshire may be impressive, but they are merely the most obvious survivals of what was once the largest religious landscape in Britain, stretching at least 25 miles from Boroughbridge in the south to Catterick in the north. This "Sacred Vale", as we have dubbed it, appears to have been of primary importance in a religious context from the late Neolithic period right through to Celtic times.

Archaeologist Dr Jan Harding, who has been investigating the area since 1995, has shown that Thornborough’s first religious monument was the Cursus. This is one of two ceremonial causeways within the Sacred Vale, the other being at Scorton near Catterick. They are two of only three cursus sites in the north of England and are among the largest in Britain.

After the cursus monuments, religious expression in the area flourished with the creation of a widespread configuration of very large monuments. Across the whole Vale, seven enormous earth henges and a large stone row were erected. This created the earliest and largest planned religious landscape within the British Isles. Six of the henges have almost identical layouts, demonstrating a significant degree of organisation within a lengthy continuity of social structure. For such large henges, the creation of two of identical construction would be significant – but six is absolutely unique!

Elsewhere in Britain, henges of earth, wood or stone were constructed in an almost piecemeal fashion yet, here in Yorkshire, they were built along two straight alignments of remarkable long distance accuracy. Nowhere else in Britain can this prehistoric complex be matched in size, accuracy and sophistication of design – and yet it has become a victim of economic exploitation by modern man!

But, unless action is taken quickly, there will be little left for heritage tourists to see. The henges at Hutton Moor and Cana Barn can now be identified only as crop marks, and that at Nunwick is little better. The whole of the cursus at Scorton and half of that at Thornborough have recently been lost to aggregates quarrying. The henge at Catterick was first bisected when the Romans built Dere Street through its centre, then it was flattened centuries later for a racecourse and, most recently, half has been destroyed by quarrying. At Boroughbridge, a modern housing estate has been allowed to intrude upon the setting of the Devil’s Arrows megaliths.

Archaeologists now recognise that it is vital to preserve and investigate the landscape setting in which significant henge monuments are situated if we are ever to understand them properly. At Stonehenge, modern research techniques are now uncovering new clues about its evolution only because the surrounding landscape was saved for the nation by English Heritage and the National Trust.

In rural Yorkshire, where the local authorities are controlled by landowners and farmers, the landscape has always been just an asset to be exploited. Since World War II, a series of open-cast gravel quarries have generated much higher rates income than traditional farming close to the Thornborough Henges, at one point even biting into the central henge. North Yorkshire County Council, which gave permission for this violation of its own cultural heritage, even took advantage of the situation to commandeer the resultant pit as a waste tip, which is still operational.

All the land to the west of the henges was quarried – and any archaeology destroyed – before the introduction in 1990 of the current Planning Policy Guidance PPG16 which sets out the government’s policy to reconcile the need for development with the need to record buried archaeology. Permission for gravel extraction in the 106 hectares of farmland to the north of the henges was granted in 1994 and this present Nosterfield Quarry is operated by Tarmac Northern Ltd. Amongst other things, PPG16 requires any archaeology to be recorded before being destroyed by a development. This particular requirement is useful in that, for the first time within the setting of the henges, we can gain some understanding of the extent of the archaeology being lost to quarrying.

Two areas of pits and hearths have been interpreted as the temporary settlements of people who came either to build the henges and/or to worship at them. There is an area where axes appear to have been ritually deposited, and another contains burials from both the Bronze and the Iron Ages. Two square barrows and horse burials from the latter period support the suggestion from the Ferrybridge chariot burial that the influence of the EastYorkshire-based Parisii tribe extended further west than had previously been suspected. This rich pattern of activity is likely to have been mirrored in those areas destroyed by earlier quarry workings – and prompts the expectation that it is likely to be replicated in the areas so far untouched by quarrying.

Dr Harding’s field walking evidence indicates that settlements were located in an annulus outside a sacred core area that surrounded the henges. Two of those probable settlements were within the perimeter of the present Nosterfield Quarry and a third is on the proposed quarry extension at Ladybridge Farm. So, on purely archaeological grounds, we contend that quarrying must stop.

We believe that our early ancestors chose these gravel terraces as a flat landscape upon which to sculpt the physical expressions – henge temples and processional ways - of a "religion" interpreting their emerging understanding of the impact of nature upon a newly evolving settled agricultural lifestyle. We also believe that the sequence of gravel quarries is destroying the ritual landscape of these internationally important henges, and that the clues left behind by our ancestors should not be destroyed in the name of short-term gain.

PPG16 requires that archaeology of national importance should be preserved in situ wherever possible, along with the setting. It also warns the developer to take out insurance in case such features are found. Clearly the intention is that newly discovered archaeology of national importance should be preserved in situ.

The County Archaeologist raised no objections to the planning application for the present Nosterfield Quarry, simply requiring the imposition of a condition to safeguard archaeological interests. The area contained no recorded monuments and, on gravel beds, it is very difficult to identify buried archaeology without excavation, so no archaeology was expected. His predecessor, Mike Griffiths, who has been in private practice for some years, carried out the required advance archaeological evaluation on behalf of the mining company.

His conclusion that, apart from a small peat deposit, "the archaeology of the site displays little potential for contributing to archaeological studies" was quoted in the County Planning Officer’s report to the elected members. However, that report omitted Mr Griffiths’ assertion that "…the area of the proposed extraction lies within, though probably at the extreme margin of, the main prehistoric ritual landscape". It appears that, contrary to S18 of PPG16, the county council did not regard the preservation of the setting of the henges, which is surely of national significance, to be a material consideration in determining that application.

The watching brief required only 2% archaeological sampling before quarrying commenced, whereas 8-10% is now required for Neolithic and Bronze Age areas. That "sampling" was implemented as a single narrow trench across the centre of the site, rather than as a checkerboard series of pits statistically representative of the entire area. Mr Griffiths has recently admitted that he failed to investigate the topsoil for Mesolithic deposits. As it is, the cursory sample excavations, largely by spade ahead of the bulldozers, found extensive archaeological evidence (ancient hearths, Neolithic pottery, three round barrows, 12 cremations and pit alignments) to justify more intensive investigations.

The first area quarried by Tarmac contained seventy Neolithic pits and thirteen hearths containing large amounts of pottery and flint. Yet because only a handful of features were expected, advance investigations took place extremely rapidly and a significant proportion of the features were not properly excavated. In the archaeologist’s own words: "we were running around, not quite chasing our tails, but under an enormous amount of pressure because the machine that was operating was an enormous great earth mover". Local people became aware of these finds only in the late Spring of 2003, the County Archaeologist having earlier denied that any information was available. According to his own Chief Executive, however, he had been given a "brief interim summary of the findings" on 7/11/02 long after those finds had been destroyed.

Rough digging of features is not likely to preserve evidence so fragile that it can "crumble in your hand". Whilst a contract archaeologist may be no less skilled than an academic, the developer- driven system initiated by PPG16 inevitably tends to deliver lowest cost not highest quality. When asked about the potential importance and preservation in situ of these remains, the County Archaeologist responded that they were unlikely to be important enough, since to stop the quarrying would entail North Yorkshire County Council paying Tarmac compensation for profits lost.

So Tarmac has achieved its ends while following the letter of the law, with the result that no features found on the current quarry have been preserved in situ. It is now evident that PPG16 and the county council’s implementation of it cannot ensure preservation in situ of archaeology on this site ~ regardless of its importance. Within the setting of the Thornborough Henges and while remaining within the law, Tarmac has devised a precedent for developers of all kinds to destroy unscheduled archaeology even when it is patently of national significance.

It appears that neither a county council nor English Heritage has the power under existing legislation to ensure preservation of nationally important features discovered after planning permission has been granted. We don’t know how much of this supposedly unimportant landscape was quarried without prior investigation. Any buried remains in the vicinity of the henges are all part of a jigsaw that holds the key to a better understanding to these amazing structures. The archaeology is complex, difficult to understand and, most importantly, is the last of a finite resource. Rescue excavation and mitigation strategies of the kind employed in the Nosterfield Quarry workings, even if impeccably implemented, are unlikely to provide an adequate response in the face of the total destruction inevitably produced by gravel extraction, especially when we do not even know what we are looking for.

Tarmac itself owns the open farmland of Thornborough Moor, together with the southern and central henges, and land at Upsland to the east. On 4 June, 2004, it submitted a planning application to the county council to extend quarrying eastwards on to Ladybridge Farm, and has announced that it wants to start quarrying Thornborough Moor by the end of this decade. Tarmac claims that recording buried archaeology at the developer’s expense before quarrying is a better option than allowing such features to be broken up by ploughing without record.

This may be a seductive prospect for those who value new knowledge at any price, particularly if they don’t feel they have any stewardship responsibilities because they live far away. But is ploughing really a serious danger at Ladybridge and Thornborough Moor? Many of the features already discovered nearby are a metre or more deep, well below ploughing depth. Take away the threat of quarrying, which guarantees the destruction of the henges’ setting, and we give ourselves time to solve any real issues with ploughing and raise the funds for unpressurised investigation of this matchless complex. In any case, if Tarmac is truly so concerned about archaeology, then, as the landowner, it could insist upon a management regime that forbids ploughing by its farmer tenants.

Open-cast quarrying is different from most other types of development as it destroys the entire landscape in its path to a depth of 6m or more and it has already completely removed much of the setting of the henges. Once quarried, entire areas of land are left archaeologically sterile. This is not the same as with a road or a building, where the impact is relatively minor and measures can be taken to preserve archaeology in the ground. Around Thornborough, when a quarry has been exhausted, an alien landscape of water-filled pits replaces the original farmland, completely obliterating the local community’s sense of the heritage of "their place." Standing on the very spot where their ancestors once progressed along a processional way generates in local people a sense of connection across the ages. That visceral feeling cannot be replaced by an interpretation board on the side of a machine-dug water-filled crater, even if the latter does provide an unwanted nature reserve or boating pool.