Drumclay crannog: Report finds errors made in roadworks damage
The destruction of part of an ancient historical site during a road scheme in County Fermanagh was due to "systematic weaknesses" and "poor human judgement", a review of the excavation has found.
The Drumclay crannog, a man-made island settlement, was situated on the route of the A32 Cherrymount link road in Enniskillen, completed in 2012.
Construction work on the £16m road scheme was disrupted and delayed.
The Audit Office estimated the extra archaeological cost was about £2.5m.
An independent review, ordered by the environment minister in 2012, has revealed that the Northern Ireland Environment Agency (NIEA) raised concerns that the road would disturb or destroy the archaeological remains of the crannog in March 2008.
A mapping error during the assessment of route options led to confusion over the crannog's location, even though it was marked accurately on maps dating from 1835 and 1860.
The review said NIEA reiterated the crannog's historical significance, the high cost of excavating or protecting it, and the need to examine the potential of rerouting the road.
However, NIEA is criticised for not acting more strongly when unauthorised work was carried out by the contractor that led to the collapse of part of the site and the destruction of archaeological deposits.
The report said the contractor admitted the breach of its licence, and this was an illegal act which could have led to a prosecutable offence.
NIEA took no further action and instead renewed the licence so that the excavation could continue.
The report adds that the conduct of the initial excavation did not meet professional standards.
However, the dig resulted in an enormous number of artefacts being recovered that the report says "will transform our understanding of crannogs and inform wider discussion of early medieval Ireland".
The crannog was occupied for more than 1,000 years, and the discoveries that were made have rewritten the history books.
Some 5,000 artefacts dating back to AD 700 were recovered, including the remains of more than 30 wooden houses and objects of bone, textile, glass, amber, pottery, metal and stone.
The report makes six recommendations to improve protocols for archaeological work on road schemes and the reviewing of licences.
Environment Minister Mark H Durkan has published an action plan to ensure changes are made and the lessons from Drumclay crannog are not forgotten.
He said implementing the report's recommendations "will help to ensure that the public interest in our archaeological heritage is better-served now and in the future".
Sinn Féin Fermanagh MLA Phil Flanagan said "lessons need to be learnt from this mess".
"The minister must explain why NIEA failed to act more strongly when the illegal activity occurred and this failure highlights, once again, the failure of NIEA to protect the environment and the need for a strong and independent Environmental Protection Agency.
"In order to improve public confidence in the NIEA as protectors of the environment, this situation needs to change."