News on HS2 in Hillingdon

Archaeologists working in on the HS2 project in West London have uncovered a fascinating rare set of Iron Age 'potins', an early version of the coin, dating back to the 1st Century BC .

The hoard of over 300 potins was discovered in Hillingdon in August last year. It is a significant historical find and may be recognised as “treasure” under British Law. ‘The Hillingdon Hoard’ – as it has been called – dates back to the late Iron Age, during a period of change as the Romans began to establish themselves in Britain and create Londinium.

The potins are based on coins struck in Marseille, France, about 2,175 years ago, which bear the left-facing head of Apollo on one side and a bull charging right on the other. The use of these early coins spread across northern Europe and in England their use was commonly linked to Kent, Essex or Hertfordshire.

The term ‘potin’ refers to the base metal silver-like alloy used in coins. It is typically a mixture of copper, tin and lead. Historians are unclear what the potins were used for during the Iron Age, particularly as the exchange of goods and service - or bartering - is thought to have been the main method of commerce at that time, nor why the coins were deposited where they were found.

The site in Hillingdon was undergoing archaeological excavation and analysis led by our enabling works contractor, Costain Skanska joint venture (CS JV) and the archaeologists involved were elated to make such a significant discovery. Archaeologists now analysing the discovery believe the potins may have been to mark the boundary of a property or as an offering to the gods - in a woodland clearing or near a sacred spring. It is not unusual for a hoard to be found in an apparently isolated location and they may also have been buried as saving hoards or as emergency hoards in times of crisis.

A hoard of a similar size, the ‘Sunbury hoard’ was discovered in 2010 but the potins were dated much earlier in the Iron Age. Potins from late in the Iron Age, similar to the Hillingdon Hoard, have been found previously but in much smaller quantities, making this find very significant.

Because of the significance of the find, and the high number of coins, the local coroner was alerted. The coroner will determine whether the discovery amounts to ‘treasure’ after considering specialist evidence from the British Museum. The potins were the removed from site for specialist cleaning, conservation and assessment.

In the London region, the oldest archaeology we have found was dated to 11,000 years ago - a period known as the Mesolithic or Middle Stone Age. From this period, stone tools and artefacts have been discovered at locations which suggested people were living on the banks of the river. This would have provided a rich supply of food and water for these hunter-gatherers to exploit. Later evidence from the Bronze Age, about 4,000 years ago, further indicates human activity near the river, with finds including cremations and a possible roundhouse. However, until the potins were uncovered no archaeological evidence of activity was encountered for almost another 3,500 years.

The value of the hoard has not yet been determined, nor has its future location. Under the Treasure Act, the coroner will determine whether the find constitutes Treasure and if a museum wishes to acquire the potins, on the advice of specialists at the British Museum the coroner will conduct an inquest at which recommendations for the find will be made and a potential value placed upon it.

The hoard was found during our works on land that was occupied temporarily. We are not making any claim on the hoard and under the Treasure Act archaeologists are not entitled to a share of any reward. Our approach to the archaeological work was developed in discussion with Historic England to ensure the site was carefully examined to find, protect or investigate important archaeology before construction begins.

We are participating in this year’s Festival of Archaeology, which begins on 19th July. A series of webinars are being held and members of the public are invited to register and find out more about this, and other, fascinating discoveries.

Find out more about the Festival of Archaeology and the events we are holding

If you have a question about HS2 or our works, please contact our HS2 Helpdesk team on 08081 434 434 or email hs2enquiries@hs2.org.uk