I have previously written about how archaeological sites as experienced by the public differ from sites as experienced by the archaeologist, how this feeds into misunderstandings of archaeology, and their impact on our society. These issues have once again come to the fore as the summer of 2023 provokes further debate about the approved A303 tunnel scheme near Stonehenge. As with the Prittlewell Prince, the debate reveals a great deal about the public understanding of archaeology, exposing misconceptions about both the nature of archaeology and the role of archaeologists. It also reveals how little many people know about archaeology in the planning process.

Archaeology and efforts to mitigate the effects of development on archaeological remains have been a part of the British planning system since 1992. Since then, Planning Policy Documents 15 and 16 (or PPG15 and PPG16), and their 2010 successor ‘Planning Policy Statement 5′ (PPS5), and the ongoing Historic Environment section of the National Planning Policy Framework, produced a vibrant commercial archaeology sector dealing with archaeology threatened by development. This sector is paid for by developers (hence ‘developer-funded archaeology’) under planning conditions imposed by local authorities. The aim of the process, from planning guidance to commercial archaeologists and archives is to identify archaeological remains likely to be affected by any new development and plan, execute, publish, and archive a process of archaeological mitigation commensurate with the importance of those remains.

My career in archaeology spans almost exactly the same, almost 25-year time period as the development of the Stonehenge Tunnel scheme. I spent my first nearly 15 years working predominantly in British commercial archaeology, with some research excavations alongside. The last 5 years of my commercial archaeology experience were spent researching and writing pre-planning historic environment desk-based assessments and environmental impact assessments. These are planning documents written before any work takes place, predicting the type of archaeological remains likely to be present on any given development site (if any) and proposing suitable mitigation strategies. This process involved researching what archaeological remains had been found in and around the site previously, predicting whether such material was likely to be found there again, assessing the significance of that material, and determining a suitable course of action based on that significance. Understanding the nature of site significance and how that affects the chosen archaeological mitigation strategy is crucial to understanding both the current proposals for the Stonehenge Tunnel and the development of those proposals alongside archaeological evaluation over the last 20 years.

Archaeological mitigation strategies

Archaeological mitigation strategies are rather limited. As I explained in a previous blog post, and as every first-year archaeology student is taught, the process of archaeological excavation is destructive! Archaeological excavation is a form of slow, controlled destruction, where contexts are unpicked steadily and recorded in detail. After the excavation is completed, the textual, visual, and digital records of the excavation, together with the artefacts, and other material represent a permanent archive of what was found. This forms the basis for both immediate post-excavation analysis and publication, and any re-assessment of the record by future researchers.

Site Significance

Since excavation means an archaeological site is effectively removed, there are obviously sites of such paramount importance that their removal, even with full archaeological excavation, is NEVER going to be ethical or reasonable. Even the fullest and most detailed excavation ever undertaken, could not justify the removal of the stone circle at Stonehenge! It is simply of too great importance nationally and internationally; its national significance is indicated by its Scheduled Monument status, and its international significance by the surrounding World Heritage Site.

At the opposite end of the significance scale are sites like the one I once dug in Peterborough. On a piece of higher ground roughly opposite the important prehistoric ritual area of Flag Fen, this particular site had been recommended for archaeological evaluation because it might have had prehistoric remains associated with the Flag Fen landscape. So we dutifully excavated a series of 19th-century drains and the odd post-medieval ditch. It was perhaps the least interesting, least important site I have ever worked on and contributed almost nothing to the sum of archaeological information about Peterborough. Once their dullness has been confirmed through evaluation test trenches, such sites need minimal mitigation. At most, a ‘watching brief‘ might take place, where an archaeologist visits the site during relevant groundworks to ensure the site continues to be as archaeologically insignificant as first thought.

In between the sites of national and international importance and those where even archaeological evaluation feels like a waste of time (even though it isn’t – evidence of absence is still evidence), lie a wide range of sites ranging from local to regional significance. Everything from a Bronze Age field system to post-medieval tenements falls into one of these categories, and almost all of them will be ‘preserved by record’ through detailed archaeological excavation. The excavation will be meticulously planned, with a ‘Written Scheme of Investigation (WSI)‘ submitted to the relevant planning authority for approval, and costs and timings factored into the development process. After excavation, scientific analysis of the results will take place followed by some form of publication, the costs borne by the developer and agreed by the planning authority. If the scientific importance of the excavation exceeds original expectations, the developer may be asked to fund additional analysis and publication, but there are also grants available for this work. Finally, the archaeological records are archived, typically with the Archaeological Data Service and local museums, in accordance with industry standards, and such that they can be retrieved by future researchers.

Occasionally, sites of broadly local or regional significance might include a nationally significant feature, such as a Scheduled Monument, which will be preserved in situ within the development. Such nationally or internationally significant features are obviously known before development begins, and their protection is typically written into the scheme of works and approved by the planning authority and stakeholders such as Historic England. At other times excavation might reveal a wholly unexpected but important find, such as the Prittlewell Prince and decisions will then be made about the feasibility of retaining important remains in situ or whether they must be excavated!

Balancing significance and development

Broadly speaking then, there are two possible mitigation strategies where archaeological remains are threatened by development; ‘preservation in situ’ (i.e. leaving the remains in the ground and ensuring the development works do not damage them) for those sites simply too important to be excavated; and ‘preservation by record’ (i.e. thorough archaeological excavation and recording) for those sites of lesser significance. In addition to the significance of the site, the chosen mitigation strategy will also take into account the feasibility of protecting the site. Although the Prittlewell Prince was undoubtedly a site of the highest regional, and possibly even national significance, it was never going to be practical to leave the burial in situ once the sealed context of the burial chamber had been breached and the value of the site became known. Opened burials are rarely left in situ because they represent a tempting target for nighthawks and looters.

For large schemes like the Stonehenge Tunnel, archaeological mitigation is often a long and complex process, which can last throughout the planning, planning enquiry, revised plans, and planning approval phases. Desk-based assessment of the initial plans may recommend a variety of further investigative measures (archaeological survey, remote sensing, evaluation trenches, test pits, boreholes), which will be undertaken in parallel with the planning process, redesign, modification of the plans, public consultation, planning enquiry etc. The results of these investigative measures inevitably inform redesigns, modifications, and the planning conditions enforced on the final proposal once it achieves approval. Revisions might include:

• redesigns to avoid highly significant or expensive to excavate (i.e. burials) archaeological remains that were not previously known;
• changes in the depth of the proposed development to preserve lower layers of archaeology in situ below the lowest level of disturbance from the development (thereby also reducing the cost of archaeological mitigation to the developer);
• additional requirements for specific excavation or analytical methods to address either the nature of the archaeology (e.g. osteological analysis of human remains prior to reburial) or the site itself (e.g. to deal with contaminated land).

Depending on the nature of the site and the timeline for development, archaeological excavation might occur either well in advance of construction (typically in rural or greenfield areas), or in parallel with it (as is often the case in urban areas). In one case, the planning process had continued for so long in parallel with the archaeological investigation, that by the time I wrote the revised desk-based assessment for the final scheme, the main archaeological excavation had taken place and all the archaeological deposits removed! But this is relatively rare (For those interested in London landmarks this particular site was 20 Fenchurch Street a.k.a. The WalkieTalkie). Generally, desk-based assessment and evaluations of various types (test pits/trenches, boreholes, survey, remote sensing, etc) take place before and during the planning process, while the main excavation phase occurs once planning approval has been received and is governed by a planning condition attached to that approval. At the end of the process, the resulting development should have ensured the preservation in situ of any archaeological remains of very high national or international significance; and the preservation by record of any other remains, contributing through excavation, analysis, and publication, to the sum of scientific knowledge about the past, and leaving a coherent archive that can be accessed by future researchers.

Critique

Like most public policies, PPG16 and its descendants were a compromise: An effort to strike a balance that ensured development took place, very highly significant heritage assets were protected, and lower significance remains were excavated in such as way as to contribute to scientific understanding and provide an archive for future research. No system is perfect and there have been legitimate cases of poor practice and poor oversight. It is perhaps overreliant on the oversight of planning authorities, the integrity of the archaeological units, and a contracting process that can prioritise cost over quality, but as I previously mentioned, the system generally works well.

Inevitably there are also those who dislike the compromise; both archaeology and development get cast as the villains by those with vested interests: Those who wish to strip back planning controls, can portray archaeology as slowing development and making it more expensive. Equally, archaeological remains are used, often inaccurately, by those arguing against development for reasons ranging from outright NIMBYism to genuine, even noble, concerns. An accurate understanding of the role of archaeology in the planning system can do much to correct inaccurate portrayals by vested interests. Misrepresentation of archaeology in the planning system is ALWAYS wrong, even when it is undertaken in the noblest of interests!

The creation of an entire field of commercial developer-funded archaeology has also fostered an unfortunate division in the discipline. Before 1992, archaeology was largely an academic discipline, with excavations led by academics and specialists, with the occasional local government unit undertaking excavations in advance of development in major cities. There are now very much two ‘archaeologies’ or ‘two cultures’ (Bradley 2006) in Britain; research archaeology led by academics; and commercial archaeology. There are certainly some theoretical differences between the ‘two cultures’ (Bradley 2006) in terms of their understanding of what archaeology is for, but much of the ‘division’ is artificial, and Jonathan Last is right when he argues that the rancour between the two is both unedifying and counterproductive. Naturally there are various units, academics, and projects already working across the research-commercial divide, but the tenor of the debate around the Stonehenge tunnel suggests there is further to go.

References

Bradley, R. 2006. ‘Bridging the Two Cultures – commercial archaeology and the study of prehistoric Britain’. The Antiquaries Journal 86, 1-13.

Notes

This post largely concentrates on archaeological (that is buried) heritage, rather than visible or upstanding structures, (such as buildings). However, since PPS5 planning policy hasn’t made any distinction between built or buried heritage. Both visible, standing remains and buried archaeology:

• are known as ‘heritage assets’
• are graded by significance;
• are subject to the same mitigation strategies of either ‘preservation in situ’ or ‘preservation by record’ – except where built structures are concerned ‘preservation by record’ means various types of ‘standing structure recording’ rather than excavation.